firebase-ios-sdk/Example/Database/Tests/Integration/FIRDatabaseQueryTests.m

/*
 * Copyright 2017 Google
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#import "FIRDatabaseQueryTests.h"
#import "FIRDatabaseQuery_Private.h"
#import "FQuerySpec.h"
#import "FTestExpectations.h"

@implementation FIRDatabaseQueryTests

- (void) testCanCreateBasicQueries {
    // Just make sure none of these throw anything

    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];

    [ref queryLimitedToFirst:10];
    [ref queryLimitedToLast:10];

    [[ref queryOrderedByKey] queryStartingAtValue:@"foo"];
    [[ref queryOrderedByKey] queryEndingAtValue:@"foo"];
    [[ref queryOrderedByKey] queryEqualToValue:@"foo"];

    [[ref queryOrderedByChild:@"index"] queryStartingAtValue:@YES];
    [[ref queryOrderedByChild:@"index"] queryStartingAtValue:@1];
    [[ref queryOrderedByChild:@"index"] queryStartingAtValue:@"foo"];
    [[ref queryOrderedByChild:@"index"] queryStartingAtValue:nil];
    [[ref queryOrderedByChild:@"index"] queryEndingAtValue:@YES];
    [[ref queryOrderedByChild:@"index"] queryEndingAtValue:@1];
    [[ref queryOrderedByChild:@"index"] queryEndingAtValue:@"foo"];
    [[ref queryOrderedByChild:@"index"] queryEndingAtValue:nil];
    [[ref queryOrderedByChild:@"index"] queryEqualToValue:@YES];
    [[ref queryOrderedByChild:@"index"] queryEqualToValue:@1];
    [[ref queryOrderedByChild:@"index"] queryEqualToValue:@"foo"];
    [[ref queryOrderedByChild:@"index"] queryEqualToValue:nil];

    [[ref queryOrderedByPriority] queryStartingAtValue:@1];
    [[ref queryOrderedByPriority] queryStartingAtValue:@"foo"];
    [[ref queryOrderedByPriority] queryStartingAtValue:nil];
    [[ref queryOrderedByPriority] queryEndingAtValue:@1];
    [[ref queryOrderedByPriority] queryEndingAtValue:@"foo"];
    [[ref queryOrderedByPriority] queryEndingAtValue:nil];
    [[ref queryOrderedByPriority] queryEqualToValue:@1];
    [[ref queryOrderedByPriority] queryEqualToValue:@"foo"];
    [[ref queryOrderedByPriority] queryEqualToValue:nil];
}

- (void) testInvalidQueryParams {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];

    XCTAssertThrows([[ref queryLimitedToFirst:100] queryLimitedToFirst:100]);
    XCTAssertThrows([[ref queryLimitedToFirst:100] queryLimitedToLast:100]);
    XCTAssertThrows([[ref queryLimitedToLast:100] queryLimitedToFirst:100]);
    XCTAssertThrows([[ref queryLimitedToLast:100] queryLimitedToLast:100]);
    XCTAssertThrows([[ref queryOrderedByPriority] queryOrderedByPriority]);
    XCTAssertThrows([[ref queryOrderedByPriority] queryOrderedByKey]);
    XCTAssertThrows([[ref queryOrderedByPriority] queryOrderedByChild:@"foo"]);
    XCTAssertThrows([[ref queryOrderedByPriority] queryOrderedByValue]);
    XCTAssertThrows([[ref queryOrderedByKey] queryOrderedByPriority]);
    XCTAssertThrows([[ref queryOrderedByKey] queryOrderedByKey]);
    XCTAssertThrows([[ref queryOrderedByKey] queryOrderedByChild:@"foo"]);
    XCTAssertThrows([[ref queryOrderedByKey] queryOrderedByValue]);
    XCTAssertThrows([[ref queryOrderedByChild:@"foo"] queryOrderedByPriority]);
    XCTAssertThrows([[ref queryOrderedByChild:@"foo"] queryOrderedByKey]);
    XCTAssertThrows([[ref queryOrderedByChild:@"foo"] queryOrderedByChild:@"foo"]);
    XCTAssertThrows([[ref queryOrderedByChild:@"foo"] queryOrderedByValue]);
    XCTAssertThrows([[ref queryOrderedByValue] queryOrderedByPriority]);
    XCTAssertThrows([[ref queryOrderedByValue] queryOrderedByKey]);
    XCTAssertThrows([[ref queryOrderedByValue] queryOrderedByChild:@"foo"]);
    XCTAssertThrows([[ref queryOrderedByValue] queryOrderedByValue]);
    XCTAssertThrows([[ref queryStartingAtValue:@"foo"] queryStartingAtValue:@"foo"]);
    XCTAssertThrows([[ref queryStartingAtValue:@"foo"] queryEqualToValue:@"foo"]);
    XCTAssertThrows([[ref queryEndingAtValue:@"foo"] queryEndingAtValue:@"foo"]);
    XCTAssertThrows([[ref queryEndingAtValue:@"foo"] queryEqualToValue:@"foo"]);
    XCTAssertThrows([[ref queryEqualToValue:@"foo"] queryStartingAtValue:@"foo"]);
    XCTAssertThrows([[ref queryEqualToValue:@"foo"] queryEndingAtValue:@"foo"]);
    XCTAssertThrows([[ref queryEqualToValue:@"foo"] queryEqualToValue:@"foo"]);
    XCTAssertThrows([[ref queryOrderedByKey] queryStartingAtValue:@"foo" childKey:@"foo"]);
    XCTAssertThrows([[ref queryOrderedByKey] queryEndingAtValue:@"foo" childKey:@"foo"]);
    XCTAssertThrows([[ref queryOrderedByKey] queryEqualToValue:@"foo" childKey:@"foo"]);
    XCTAssertThrows([[ref queryOrderedByKey] queryStartingAtValue:@1 childKey:@"foo"]);
    XCTAssertThrows([[ref queryOrderedByKey] queryStartingAtValue:@YES]);
    XCTAssertThrows([[ref queryOrderedByKey] queryEndingAtValue:@1]);
    XCTAssertThrows([[ref queryOrderedByKey] queryEndingAtValue:@YES]);
    XCTAssertThrows([[ref queryOrderedByKey] queryStartingAtValue:nil]);
    XCTAssertThrows([[ref queryOrderedByKey] queryEndingAtValue:nil]);
    XCTAssertThrows([[ref queryOrderedByKey] queryEqualToValue:nil]);
    XCTAssertThrows([[ref queryStartingAtValue:@"foo" childKey:@"foo"] queryOrderedByKey]);
    XCTAssertThrows([[ref queryEndingAtValue:@"foo" childKey:@"foo"] queryOrderedByKey]);
    XCTAssertThrows([[ref queryEqualToValue:@"foo" childKey:@"foo"] queryOrderedByKey]);
    XCTAssertThrows([[ref queryStartingAtValue:@1] queryOrderedByKey]);
    XCTAssertThrows([[ref queryStartingAtValue:@YES] queryOrderedByKey]);
    XCTAssertThrows([[ref queryEndingAtValue:@1] queryOrderedByKey]);
    XCTAssertThrows([[ref queryEndingAtValue:@YES] queryOrderedByKey]);
    XCTAssertThrows([ref queryStartingAtValue:@[]]);
    XCTAssertThrows([ref queryStartingAtValue:@{}]);
    XCTAssertThrows([ref queryEndingAtValue:@[]]);
    XCTAssertThrows([ref queryEndingAtValue:@{}]);
    XCTAssertThrows([ref queryEqualToValue:@[]]);
    XCTAssertThrows([ref queryEqualToValue:@{}]);

    XCTAssertThrows([[ref queryOrderedByKey] queryOrderedByPriority], @"Cannot call orderBy multiple times");
    XCTAssertThrows([[ref queryOrderedByChild:@"foo"] queryOrderedByPriority], @"Cannot call orderBy multiple times");
    XCTAssertThrows([[ref queryOrderedByKey] queryOrderedByKey], @"Cannot call orderBy multiple times");
    XCTAssertThrows([[ref queryOrderedByChild:@"foo"] queryOrderedByKey], @"Cannot call orderBy multiple times");
    XCTAssertThrows([[ref queryOrderedByKey] queryOrderedByChild:@"foo"], @"Cannot call orderBy multiple times");
    XCTAssertThrows([[ref queryOrderedByChild:@"foo"] queryOrderedByChild:@"foo"], @"Cannot call orderBy multiple times");

    XCTAssertThrows([[ref queryOrderedByKey] queryStartingAtValue:@"a" childKey:@"b"], @"Cannot specify starting child name when ordering by key.");
    XCTAssertThrows([[ref queryOrderedByKey] queryEndingAtValue:@"a" childKey:@"b"], @"Cannot specify ending child name when ordering by key.");
    XCTAssertThrows([[ref queryOrderedByKey] queryEqualToValue:@"a" childKey:@"b"], @"Cannot specify equalTo child name when ordering by key.");

    XCTAssertThrows([[ref queryOrderedByPriority] queryStartingAtValue:@YES], @"Can't pass booleans as start/end when using priority index.");
    XCTAssertThrows([[ref queryOrderedByPriority] queryEndingAtValue:@NO], @"Can't pass booleans as start/end when using priority index.");
    XCTAssertThrows([[ref queryOrderedByPriority] queryEqualToValue:@YES], @"Can't pass booleans as start/end when using priority index.");
}

- (void) testLimitRanges
{
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];
    XCTAssertThrows([ref queryLimitedToLast:0], @"Can't pass zero as limit");
    XCTAssertThrows([ref queryLimitedToFirst:0], @"Can't pass zero as limit");
    XCTAssertThrows([ref queryLimitedToLast:0], @"Can't pass zero as limit");
    uint64_t MAX_ALLOWED_VALUE = (1l << 31) - 1;
    [ref queryLimitedToFirst:MAX_ALLOWED_VALUE];
    [ref queryLimitedToLast:MAX_ALLOWED_VALUE];
    XCTAssertThrows([ref queryLimitedToFirst:(MAX_ALLOWED_VALUE+1)], @"Can't pass limits that don't fit into 32 bit signed integer range");
    XCTAssertThrows([ref queryLimitedToLast:(MAX_ALLOWED_VALUE+1)], @"Can't pass limits that don't fit into 32 bit signed integer range");
}

- (void) testInvalidKeys {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];
    NSArray* badKeys = @[ @".test", @"test.", @"fo$o", @"[what", @"ever]", @"ha#sh", @"/thing", @"th/ing", @"thing/"];

    for (NSString* badKey in badKeys) {
        XCTAssertThrows([[ref queryOrderedByPriority] queryStartingAtValue:nil childKey:badKey], @"Setting bad key");
        XCTAssertThrows([[ref queryOrderedByPriority] queryEndingAtValue:nil childKey:badKey], @"Setting bad key");
    }
}

- (void) testOffCanBeCalledOnDefault {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];

    __block BOOL called = NO;
    FIRDatabaseQuery * query = [ref queryLimitedToLast:5];
    [query observeEventType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
        if (called) {
            XCTFail(@"Should not be called twice");
        } else {
            called = YES;
        }
    }];

    [ref setValue:@{@"a": @5, @"b": @6}];

    [self waitUntil:^BOOL{
        return called;
    }];

    called = NO;

    [ref removeAllObservers];

    __block BOOL complete = NO;
    [ref setValue:@{@"a": @6, @"b": @7} withCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
        complete = YES;
    }];

    [self waitUntil:^BOOL{
        return complete;
    }];

    XCTAssertFalse(called, @"Should not have been called again");
}

- (void) testOffCanBeCalledOnHandle {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];

    __block BOOL called = NO;
    FIRDatabaseQuery * query = [ref queryLimitedToLast:5];
    FIRDatabaseHandle handle = [query observeEventType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
        if (called) {
            XCTFail(@"Should not be called twice");
        } else {
            called = YES;
        }
    }];

    [ref setValue:@{@"a": @5, @"b": @6}];

    [self waitUntil:^BOOL{
        return called;
    }];

    called = NO;

    [ref removeObserverWithHandle:handle];

    __block BOOL complete = NO;
    [ref setValue:@{@"a": @6, @"b": @7} withCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
        complete = YES;
    }];

    [self waitUntil:^BOOL{
        return complete;
    }];

    XCTAssertFalse(called, @"Should not have been called again");
}

- (void) testOffCanBeCalledOnSpecificQuery {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];

    __block BOOL called = NO;
    FIRDatabaseQuery * query = [ref queryLimitedToLast:5];
    FIRDatabaseHandle handle = [query observeEventType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
        if (called) {
            XCTFail(@"Should not be called twice");
        } else {
            called = YES;
        }
    }];

    [ref setValue:@{@"a": @5, @"b": @6}];

    [self waitUntil:^BOOL{
        return called;
    }];

    called = NO;

    [query removeObserverWithHandle:handle];

    __block BOOL complete = NO;
    [ref setValue:@{@"a": @6, @"b": @7} withCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
        complete = YES;
    }];

    [self waitUntil:^BOOL{
        return complete;
    }];

    XCTAssertFalse(called, @"Should not have been called again");
}

- (void) testOffCanBeCalledOnMultipleQueries {
    FIRDatabaseQuery *query = [[FTestHelpers getRandomNode] queryLimitedToFirst:10];
    FIRDatabaseHandle handle1 = [query observeEventType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
    }];
    FIRDatabaseHandle handle2 = [query observeEventType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
    }];
    [query removeObserverWithHandle:handle1];
    [query removeObserverWithHandle:handle2];
}

- (void) testOffCanBeCalledWithoutHandle {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];

    __block BOOL called1 = NO;
    __block BOOL called2 = NO;
    FIRDatabaseQuery * query = [ref queryLimitedToLast:5];
    [ref observeEventType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
        called1 = YES;
    }];
    [query observeEventType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
        called2 = YES;
    }];

    [ref setValue:@{@"a": @5, @"b": @6}];

    [self waitUntil:^BOOL{
        return called1 && called2;
    }];

    called1 = NO;
    called2 = NO;

    [ref removeAllObservers];

    __block BOOL complete = NO;
    [ref setValue:@{@"a": @6, @"b": @7} withCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
        complete = YES;
    }];

    [self waitUntil:^BOOL{
        return complete;
    }];

    XCTAssertFalse(called1 || called2, @"Should not have called either callback");
}

- (void) testEnsureOnly5ItemsAreKept {
    __block FIRDataSnapshot * snap = nil;
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];

    FIRDatabaseQuery * query = [ref queryLimitedToLast:5];
    __block int count = 0;
    [query observeEventType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
        snap = snapshot;
        count++;
    }];

    [ref setValue:nil];
    for (int i = 0; i < 10; ++i) {
        [[ref childByAutoId] setValue:[NSNumber numberWithInt:i]];
    }

    [self waitUntil:^BOOL{
        // The initial set triggers the callback, so we need to wait for 11 events
        return count == 11;
    }];

    count = 5;
    for (FIRDataSnapshot * snapshot in snap.children) {
        NSNumber* num = [snapshot value];
        NSNumber* current = [NSNumber numberWithInt:count];
        XCTAssertTrue([num isEqualToNumber:current], @"Expect children in order");
        count++;
    }

    XCTAssertTrue(count == 10, @"Expected 5 children");
}

- (void) testOnlyLast5SentFromServer {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];
    __block int count = 0;

    [ref setValue:nil];

    for (int i = 0; i < 10; ++i) {
        [[ref childByAutoId] setValue:[NSNumber numberWithInt:i] withCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
            count++;
        }];
    }

    [self waitUntil:^BOOL{
        return count == 10;
    }];

    FIRDatabaseQuery * query = [ref queryLimitedToLast:5];
    count = 5;
    [query observeEventType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
        for (FIRDataSnapshot *child in snapshot.children) {
            NSNumber *num = [child value];
            NSNumber *current = [NSNumber numberWithInt:count];
            XCTAssertTrue([num isEqualToNumber:current], @"Expect children to be in order");
            count++;
        }
    }];

    [self waitUntil:^BOOL{
        return count == 10;
    }];
}

- (void) testVariousLimits {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];
    FTestExpectations* expectations = [[FTestExpectations alloc] initFrom:self];

    [expectations addQuery:[ref queryLimitedToLast:1] withExpectation:@{@"c": @3}];
    [expectations addQuery:[[[ref queryOrderedByPriority] queryEndingAtValue:nil] queryLimitedToLast:1] withExpectation:@{@"c": @3}];
    [expectations addQuery:[[[ref queryOrderedByPriority] queryEndingAtValue:nil] queryLimitedToLast:2] withExpectation:@{@"b": @2, @"c": @3}];
    [expectations addQuery:[[[ref queryOrderedByPriority] queryEndingAtValue:nil] queryLimitedToLast:3] withExpectation:@{@"a": @1, @"b": @2, @"c": @3}];
    [expectations addQuery:[[[ref queryOrderedByPriority] queryEndingAtValue:nil] queryLimitedToLast:4] withExpectation:@{@"a": @1, @"b": @2, @"c": @3}];


    __block BOOL ready = NO;
    [ref setValue:@{@"a": @1, @"b": @2, @"c": @3} withCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
        ready = YES;
    }];

    [self waitUntil:^BOOL{
        return ready;
    }];

    [expectations validate];
}

- (void) testSetLimitsWithStartAt {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];
    FTestExpectations* expectations = [[FTestExpectations alloc] initFrom:self];

    [expectations addQuery:[[[ref queryOrderedByPriority] queryStartingAtValue:nil] queryLimitedToFirst:1] withExpectation:@{@"a": @1}];
    [expectations addQuery:[[[ref queryOrderedByPriority] queryStartingAtValue:nil childKey:@"c"] queryLimitedToFirst:1] withExpectation:@{@"c": @3}];
    [expectations addQuery:[[[ref queryOrderedByPriority] queryStartingAtValue:nil childKey:@"b"] queryLimitedToFirst:1] withExpectation:@{@"b": @2}];
    [expectations addQuery:[[[ref queryOrderedByPriority] queryStartingAtValue:nil childKey:@"b"] queryLimitedToFirst:2] withExpectation:@{@"b": @2, @"c": @3}];
    [expectations addQuery:[[[ref queryOrderedByPriority] queryStartingAtValue:nil childKey:@"b"] queryLimitedToFirst:3] withExpectation:@{@"b": @2, @"c": @3}];


    __block BOOL ready = NO;
    [ref setValue:@{@"a": @1, @"b": @2, @"c": @3} withCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
        ready = YES;
    }];

    [self waitUntil:^BOOL{
        return ready;
    }];

    [expectations validate];
}

- (void) testLimitsAndStartAtWithServerData {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];

    __block BOOL ready = NO;
    [ref setValue:@{@"a": @1, @"b": @2, @"c": @3} withCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
        ready = YES;
    }];

    [self waitUntil:^BOOL{
        return ready;
    }];

    FTestExpectations* expectations = [[FTestExpectations alloc] initFrom:self];

    [expectations addQuery:[[[ref queryOrderedByPriority] queryStartingAtValue:nil] queryLimitedToFirst:1] withExpectation:@{@"a": @1}];

    /*params = [[FQueryParams alloc] init];
    params = [params setStartPriority:nil andName:@"c"];
    params = [params limitTo:1];
    [expectations addQuery:[ref queryWithParams:params] withExpectation:@{@"c": @3}];

    params = [[FQueryParams alloc] init];
    params = [params setStartPriority:nil andName:@"b"];
    params = [params limitTo:1];
    [expectations addQuery:[ref queryWithParams:params] withExpectation:@{@"b": @2}];

    params = [[FQueryParams alloc] init];
    params = [params setStartPriority:nil andName:@"b"];
    params = [params limitTo:2];
    [expectations addQuery:[ref queryWithParams:params] withExpectation:@{@"b": @2, @"c": @3}];

    params = [[FQueryParams alloc] init];
    params = [params setStartPriority:nil andName:@"b"];
    params = [params limitTo:3];
    [expectations addQuery:[ref queryWithParams:params] withExpectation:@{@"b": @2, @"c": @3}];*/

    [self waitUntil:^BOOL{
        return expectations.isReady;
    }];
    [expectations validate];
    [ref removeAllObservers];
}

- (void) testChildEventsAreFiredWhenLimitIsHit {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];

    NSMutableArray* added = [[NSMutableArray alloc] init];
    NSMutableArray* removed = [[NSMutableArray alloc] init];
    [[ref queryLimitedToLast:2] observeEventType:FIRDataEventTypeChildAdded withBlock:^(FIRDataSnapshot *snapshot) {

        [added addObject:[snapshot key]];
    }];
    [[ref queryLimitedToLast:2] observeEventType:FIRDataEventTypeChildRemoved withBlock:^(FIRDataSnapshot *snapshot) {

        [removed addObject:[snapshot key]];
    }];

    __block BOOL ready = NO;
    [ref setValue:@{@"a": @1, @"b": @2, @"c": @3} withCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
        ready = YES;
    }];

    [self waitUntil:^BOOL{
        return ready;
    }];

    XCTAssertTrue([removed count] == 0, @"Nothing should be removed from our window");
    NSArray* expected = @[@"b", @"c"];
    XCTAssertTrue([added isEqualToArray:expected], @"Should have two items");

    [added removeAllObjects];
    ready = NO;
    [[ref child:@"d"] setValue:@4 withCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
        ready = YES;
    }];

    [self waitUntil:^BOOL{
        return ready;
    }];

    expected = @[@"b"];
    XCTAssertTrue([removed isEqualToArray:expected], @"Expected to remove b");
    expected = @[@"d"];
    XCTAssertTrue([added isEqualToArray:expected], @"Expected to add d");
    [ref removeAllObservers];
}

- (void) testChildEventsAreFiredWhenLimitIsHitWithServerData {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];

    __block BOOL ready = NO;
    [ref setValue:@{@"a": @1, @"b": @2, @"c": @3} withCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
        ready = YES;
    }];

    [self waitUntil:^BOOL{
        return ready;
    }];

    NSMutableArray* added = [[NSMutableArray alloc] init];
    NSMutableArray* removed = [[NSMutableArray alloc] init];
    FIRDatabaseQuery * query = [ref queryLimitedToLast:2];
    [query observeEventType:FIRDataEventTypeChildAdded withBlock:^(FIRDataSnapshot *snapshot) {

        [added addObject:[snapshot key]];
    }];
    [query observeEventType:FIRDataEventTypeChildRemoved withBlock:^(FIRDataSnapshot *snapshot) {

        [removed addObject:[snapshot key]];
    }];

    [self waitUntil:^BOOL{
        return [added count] == 2;
    }];

    XCTAssertTrue([removed count] == 0, @"Nothing should be removed from our window");
    NSArray* expected = @[@"b", @"c"];
    XCTAssertTrue([added isEqualToArray:expected], @"Should have two items");

    [added removeAllObjects];
    ready = NO;
    [[ref child:@"d"] setValue:@4 withCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
        ready = YES;
    }];

    [self waitUntil:^BOOL{
        return ready;
    }];

    expected = @[@"b"];
    XCTAssertTrue([removed isEqualToArray:expected], @"Expected to remove b");
    expected = @[@"d"];
    XCTAssertTrue([added isEqualToArray:expected], @"Expected to add d");
    [ref removeAllObservers];
}

- (void) testChildEventsAreFiredWhenLimitIsHitWithStart {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];

    FIRDatabaseQuery * query = [[[ref queryOrderedByPriority] queryStartingAtValue:nil childKey:@"a"] queryLimitedToFirst:2];

    NSMutableArray* added = [[NSMutableArray alloc] init];
    NSMutableArray* removed = [[NSMutableArray alloc] init];
    [query observeEventType:FIRDataEventTypeChildAdded withBlock:^(FIRDataSnapshot *snapshot) {

        [added addObject:[snapshot key]];
    }];
    [query observeEventType:FIRDataEventTypeChildRemoved withBlock:^(FIRDataSnapshot *snapshot) {

        [removed addObject:[snapshot key]];
    }];

    __block BOOL ready = NO;
    [ref setValue:@{@"a": @1, @"b": @2, @"c": @3} withCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
        ready = YES;
    }];

    [self waitUntil:^BOOL{
        return ready;
    }];

    XCTAssertTrue([removed count] == 0, @"Nothing should be removed from our window");
    NSArray* expected = @[@"a", @"b"];
    XCTAssertTrue([added isEqualToArray:expected], @"Should have two items");

    [added removeAllObjects];
    ready = NO;
    [[ref child:@"aa"] setValue:@4 withCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
        ready = YES;
    }];

    [self waitUntil:^BOOL{
        return ready;
    }];

    expected = @[@"b"];
    XCTAssertTrue([removed isEqualToArray:expected], @"Expected to remove b");
    expected = @[@"aa"];
    XCTAssertTrue([added isEqualToArray:expected], @"Expected to add aa");
    [ref removeAllObservers];
}

- (void) testChildEventsAreFiredWhenLimitIsHitWithStartAndServerData {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];

    __block BOOL ready = NO;
    [ref setValue:@{@"a": @1, @"b": @2, @"c": @3} withCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
        ready = YES;
    }];

    [self waitUntil:^BOOL{
        return ready;
    }];

    FIRDatabaseQuery * query = [[[ref queryOrderedByPriority] queryStartingAtValue:nil childKey:@"a"] queryLimitedToFirst:2];
    NSMutableArray* added = [[NSMutableArray alloc] init];
    NSMutableArray* removed = [[NSMutableArray alloc] init];
    [query observeEventType:FIRDataEventTypeChildAdded withBlock:^(FIRDataSnapshot *snapshot) {

        [added addObject:[snapshot key]];
    }];
    [query observeEventType:FIRDataEventTypeChildRemoved withBlock:^(FIRDataSnapshot *snapshot) {

        [removed addObject:[snapshot key]];
    }];

    [self waitUntil:^BOOL{
        return [added count] == 2;
    }];

    XCTAssertTrue([removed count] == 0, @"Nothing should be removed from our window");
    NSArray* expected = @[@"a", @"b"];
    XCTAssertTrue([added isEqualToArray:expected], @"Should have two items");

    [added removeAllObjects];
    ready = NO;
    [[ref child:@"aa"] setValue:@4 withCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
        ready = YES;
    }];

    [self waitUntil:^BOOL{
        return ready;
    }];

    expected = @[@"b"];
    XCTAssertTrue([removed isEqualToArray:expected], @"Expected to remove b");
    expected = @[@"aa"];
    XCTAssertTrue([added isEqualToArray:expected], @"Expected to add aa");
    [ref removeAllObservers];
}

- (void) testStartAndLimitWithIncompleteWindow {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];

    FIRDatabaseQuery * query = [[[ref queryOrderedByPriority] queryStartingAtValue:nil childKey:@"a"] queryLimitedToFirst:2];
    NSMutableArray* added = [[NSMutableArray alloc] init];
    NSMutableArray* removed = [[NSMutableArray alloc] init];
    [query observeEventType:FIRDataEventTypeChildAdded withBlock:^(FIRDataSnapshot *snapshot) {
        [added addObject:[snapshot key]];
    }];
    [query observeEventType:FIRDataEventTypeChildRemoved withBlock:^(FIRDataSnapshot *snapshot) {

        [removed addObject:[snapshot key]];
    }];

    __block BOOL ready = NO;
    [ref setValue:@{@"c": @3} withCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
        ready = YES;
    }];

    [self waitUntil:^BOOL{
        return ready && [added count] >= 1;
    }];

    XCTAssertTrue([removed count] == 0, @"Nothing should be removed from our window");
    NSArray* expected = @[@"c"];
    XCTAssertTrue([added isEqualToArray:expected], @"Should have one item");

    [added removeAllObjects];
    ready = NO;
    [[ref child:@"b"] setValue:@4 withCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
        ready = YES;
    }];

    [self waitUntil:^BOOL{
        return ready;
    }];

    XCTAssertTrue([removed count] == 0, @"Expected to remove nothing");
    expected = @[@"b"];
    XCTAssertTrue([added isEqualToArray:expected], @"Expected to add b");
    [ref removeAllObservers];
}

- (void) testStartAndLimitWithIncompleteWindowAndServerData {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];

    __block BOOL ready = NO;
    [ref setValue:@{@"c": @3} withCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
        ready = YES;
    }];

    [self waitUntil:^BOOL{
        return ready;
    }];

    FIRDatabaseQuery * query = [[[ref queryOrderedByPriority] queryStartingAtValue:nil childKey:@"a"] queryLimitedToFirst:2];

    NSMutableArray* added = [[NSMutableArray alloc] init];
    NSMutableArray* removed = [[NSMutableArray alloc] init];
    [query observeEventType:FIRDataEventTypeChildAdded withBlock:^(FIRDataSnapshot *snapshot) {

        [added addObject:[snapshot key]];
    }];
    [query observeEventType:FIRDataEventTypeChildRemoved withBlock:^(FIRDataSnapshot *snapshot) {

        [removed addObject:[snapshot key]];
    }];

    [self waitUntil:^BOOL{
        return [added count] == 1;
    }];

    XCTAssertTrue([removed count] == 0, @"Nothing should be removed from our window");
    NSArray* expected = @[@"c"];
    XCTAssertTrue([added isEqualToArray:expected], @"Should have one item");

    [added removeAllObjects];
    ready = NO;
    [[ref child:@"b"] setValue:@4 withCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
        ready = YES;
    }];

    [self waitUntil:^BOOL{
        return ready;
    }];

    XCTAssertTrue([removed count] == 0, @"Expected to remove nothing");
    expected = @[@"b"];
    XCTAssertTrue([added isEqualToArray:expected], @"Expected to add b");
    [ref removeAllObservers];
}

- (void) testChildEventsFiredWhenItemDeleted {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];

    FIRDatabaseQuery * query = [ref queryLimitedToLast:2];

    NSMutableArray* added = [[NSMutableArray alloc] init];
    NSMutableArray* removed = [[NSMutableArray alloc] init];
    [query observeEventType:FIRDataEventTypeChildAdded withBlock:^(FIRDataSnapshot *snapshot) {
        [added addObject:[snapshot key]];
    }];
    [query observeEventType:FIRDataEventTypeChildRemoved withBlock:^(FIRDataSnapshot *snapshot) {

        [removed addObject:[snapshot key]];
    }];

    __block BOOL ready = NO;
    [ref setValue:@{@"a": @1, @"b": @2, @"c": @3} withCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
        ready = YES;
    }];

    [self waitUntil:^BOOL{
        return ready && [added count] >= 1;
    }];

    XCTAssertTrue([removed count] == 0, @"Nothing should be removed from our window");
    NSArray* expected = @[@"b", @"c"];
    XCTAssertTrue([added isEqualToArray:expected], @"Should have one item");

    [added removeAllObjects];
    ready = NO;
    [[ref child:@"b"] removeValueWithCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
        ready = YES;
    }];

    [self waitUntil:^BOOL{
        return ready;
    }];

    expected = @[@"b"];
    XCTAssertTrue([removed isEqualToArray:expected], @"Expected to remove b");
    expected = @[@"a"];
    XCTAssertTrue([added isEqualToArray:expected], @"Expected to add a");
    [ref removeAllObservers];
}

-(void) testChildEventsAreFiredWhenItemDeletedAtServer {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNodeWithoutPersistence];

    __block BOOL ready = NO;
    [ref setValue:@{@"a": @1, @"b": @2, @"c": @3} withCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
        ready = YES;
    }];

    [self waitUntil:^BOOL{
        return ready;
    }];

    FIRDatabaseQuery * query = [ref queryLimitedToLast:2];

    NSMutableArray* added = [[NSMutableArray alloc] init];
    NSMutableArray* removed = [[NSMutableArray alloc] init];
    [query observeEventType:FIRDataEventTypeChildAdded withBlock:^(FIRDataSnapshot *snapshot) {

        [added addObject:[snapshot key]];
    }];
    [query observeEventType:FIRDataEventTypeChildRemoved withBlock:^(FIRDataSnapshot *snapshot) {

        [removed addObject:[snapshot key]];
    }];

    [self waitUntil:^BOOL{
        return [added count] == 2;
    }];

    XCTAssertTrue([removed count] == 0, @"Nothing should be removed from our window");
    NSArray* expected = @[@"b", @"c"];
    XCTAssertTrue([added isEqualToArray:expected], @"Should have two items");

    [added removeAllObjects];
    ready = NO;
    [[ref child:@"b"] removeValueWithCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
        ready = YES;
    }];

    [self waitUntil:^BOOL{
        return ready;
    }];

    XCTAssertEqualObjects(removed, (@[@"b"]), @"Expected to remove b");
    XCTAssertEqualObjects(added, (@[@"a"]), @"Expected to add a");
    [ref removeAllObservers];
}

- (void) testRemoveFiredWhenItemDeleted {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];

    FIRDatabaseQuery * query = [ref queryLimitedToLast:2];
    NSMutableArray* added = [[NSMutableArray alloc] init];
    NSMutableArray* removed = [[NSMutableArray alloc] init];
    [query observeEventType:FIRDataEventTypeChildAdded withBlock:^(FIRDataSnapshot *snapshot) {
        [added addObject:[snapshot key]];
    }];
    [query observeEventType:FIRDataEventTypeChildRemoved withBlock:^(FIRDataSnapshot *snapshot) {

        [removed addObject:[snapshot key]];
    }];

    __block BOOL ready = NO;
    [ref setValue:@{@"b": @2, @"c": @3} withCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
        ready = YES;
    }];

    [self waitUntil:^BOOL{
        return ready && [added count] >= 1;
    }];

    XCTAssertTrue([removed count] == 0, @"Nothing should be removed from our window");
    NSArray* expected = @[@"b", @"c"];
    XCTAssertTrue([added isEqualToArray:expected], @"Should have one item");

    [added removeAllObjects];
    ready = NO;
    [[ref child:@"b"] removeValueWithCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
        ready = YES;
    }];

    [self waitUntil:^BOOL{
        return ready;
    }];

    expected = @[@"b"];
    XCTAssertTrue([removed isEqualToArray:expected], @"Expected to remove b");
    XCTAssertTrue([added count] == 0, @"Expected to add nothing");
    [ref removeAllObservers];
}

-(void) testRemoveFiredWhenItemDeletedAtServer {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];

    __block BOOL ready = NO;
    [ref setValue:@{@"b": @2, @"c": @3} withCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
        ready = YES;
    }];

    [self waitUntil:^BOOL{
        return ready;
    }];

    FIRDatabaseQuery * query = [ref queryLimitedToLast:2];

    NSMutableArray* added = [[NSMutableArray alloc] init];
    NSMutableArray* removed = [[NSMutableArray alloc] init];
    [query observeEventType:FIRDataEventTypeChildAdded withBlock:^(FIRDataSnapshot *snapshot) {

        [added addObject:[snapshot key]];
    }];
    [query observeEventType:FIRDataEventTypeChildRemoved withBlock:^(FIRDataSnapshot *snapshot) {

        [removed addObject:[snapshot key]];
    }];

    [self waitUntil:^BOOL{
        return [added count] == 2;
    }];

    XCTAssertTrue([removed count] == 0, @"Nothing should be removed from our window");
    NSArray* expected = @[@"b", @"c"];
    XCTAssertTrue([added isEqualToArray:expected], @"Should have two items");

    [added removeAllObjects];
    ready = NO;
    [[ref child:@"b"] removeValueWithCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
        ready = YES;
    }];

    [self waitUntil:^BOOL{
        return ready;
    }];

    expected = @[@"b"];
    XCTAssertTrue([removed isEqualToArray:expected], @"Expected to remove b");
    XCTAssertTrue([added count] == 0, @"Expected to add nothing");
    [ref removeAllObservers];
}

- (void) testStartAtPriorityAndEndAtPriorityWork {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];
    FTestExpectations* expectations = [[FTestExpectations alloc] initFrom:self];

    [expectations addQuery:[[[ref queryOrderedByPriority] queryStartingAtValue:@"w"] queryEndingAtValue:@"y"] withExpectation:@{@"b": @2, @"c": @3, @"d": @4}];
    [expectations addQuery:[[[ref queryOrderedByPriority] queryStartingAtValue:@"w"] queryEndingAtValue:@"w"] withExpectation:@{@"d": @4}];

    __block id nullSnap = @"dummy";
    [[[[ref queryOrderedByPriority] queryStartingAtValue:@"a"] queryEndingAtValue:@"c"] observeEventType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
        nullSnap = [snapshot value];
    }];

    [ref setValue:@{
        @"a": @{@".value": @1, @".priority": @"z"},
        @"b": @{@".value": @2, @".priority": @"y"},
        @"c": @{@".value": @3, @".priority": @"x"},
        @"d": @{@".value": @4, @".priority": @"w"}
     }];

    WAIT_FOR(expectations.isReady && [nullSnap isEqual:[NSNull null]]);

    [expectations validate];
}

- (void) testStartAtPriorityAndEndAtPriorityWorkWithServerData {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];

    __block BOOL ready = NO;
    [ref setValue:@{
     @"a": @{@".value": @1, @".priority": @"z"},
     @"b": @{@".value": @2, @".priority": @"y"},
     @"c": @{@".value": @3, @".priority": @"x"},
     @"d": @{@".value": @4, @".priority": @"w"}
     } withCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
         ready = YES;
     }];

    WAIT_FOR(ready);

    FTestExpectations* expectations = [[FTestExpectations alloc] initFrom:self];

    [expectations addQuery:[[[ref queryOrderedByPriority] queryStartingAtValue:@"w"] queryEndingAtValue:@"y"] withExpectation:@{@"b": @2, @"c": @3, @"d": @4}];
    [expectations addQuery:[[[ref queryOrderedByPriority] queryStartingAtValue:@"w"] queryEndingAtValue:@"w"] withExpectation:@{@"d": @4}];

    __block id nullSnap = @"dummy";
    [[[[ref queryOrderedByPriority] queryStartingAtValue:@"a"] queryEndingAtValue:@"c"] observeEventType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
        nullSnap = [snapshot value];
    }];

    WAIT_FOR(expectations.isReady && [nullSnap isEqual:[NSNull null]]);

    [expectations validate];
}

- (void) testStartAtAndEndAtPriorityAndNameWork {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];
    FTestExpectations* expectations = [[FTestExpectations alloc] initFrom:self];

    FIRDatabaseQuery * query = [[[ref queryOrderedByPriority] queryStartingAtValue:@1 childKey:@"a"] queryEndingAtValue:@2 childKey:@"d"];
    [expectations addQuery:query withExpectation:@{@"a": @1, @"b": @2, @"c": @3, @"d": @4}];

    query = [[[ref queryOrderedByPriority] queryStartingAtValue:@1 childKey:@"b"] queryEndingAtValue:@2 childKey:@"c"];
    [expectations addQuery:query withExpectation:@{@"b": @2, @"c": @3}];

    query = [[[ref queryOrderedByPriority] queryStartingAtValue:@1 childKey:@"c"] queryEndingAtValue:@2];
    [expectations addQuery:query withExpectation:@{@"c": @3, @"d": @4}];

    [ref setValue:@{
     @"a": @{@".value": @1, @".priority": @1},
     @"b": @{@".value": @2, @".priority": @1},
     @"c": @{@".value": @3, @".priority": @2},
     @"d": @{@".value": @4, @".priority": @2}
     }];

    WAIT_FOR(expectations.isReady);

    [expectations validate];
}

- (void) testStartAtAndEndAtPriorityAndNameWorkWithServerData {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];
    __block BOOL ready = NO;
    [ref setValue:@{
     @"a": @{@".value": @1, @".priority": @1},
     @"b": @{@".value": @2, @".priority": @1},
     @"c": @{@".value": @3, @".priority": @2},
     @"d": @{@".value": @4, @".priority": @2}
     } withCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
         ready = YES;
     }];

    WAIT_FOR(ready);

    FTestExpectations* expectations = [[FTestExpectations alloc] initFrom:self];

    FIRDatabaseQuery * query = [[[ref queryOrderedByPriority] queryStartingAtValue:@1 childKey:@"a"] queryEndingAtValue:@2 childKey:@"d"];
    [expectations addQuery:query withExpectation:@{@"a": @1, @"b": @2, @"c": @3, @"d": @4}];

    query = [[[ref queryOrderedByPriority] queryStartingAtValue:@1 childKey:@"b"] queryEndingAtValue:@2 childKey:@"c"];
    [expectations addQuery:query withExpectation:@{@"b": @2, @"c": @3}];

    query = [[[ref queryOrderedByPriority] queryStartingAtValue:@1 childKey:@"c"] queryEndingAtValue:@2];
    [expectations addQuery:query withExpectation:@{@"c": @3, @"d": @4}];

    WAIT_FOR(expectations.isReady);

    [expectations validate];
}

- (void) testStartAtAndEndAtPriorityAndNameWork2 {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];
    FTestExpectations* expectations = [[FTestExpectations alloc] initFrom:self];

    FIRDatabaseQuery * query = [[[ref queryOrderedByPriority] queryStartingAtValue:@1 childKey:@"c"] queryEndingAtValue:@2 childKey:@"b"];
    [expectations addQuery:query withExpectation:@{@"a": @1, @"b": @2, @"c": @3, @"d": @4}];

    query = [[[ref queryOrderedByPriority] queryStartingAtValue:@1 childKey:@"d"] queryEndingAtValue:@2 childKey:@"a"];
    [expectations addQuery:query withExpectation:@{@"d": @4, @"a": @1}];

    query = [[[ref queryOrderedByPriority] queryStartingAtValue:@1 childKey:@"e"] queryEndingAtValue:@2];
    [expectations addQuery:query withExpectation:@{@"a": @1, @"b": @2}];

    [ref setValue:@{
     @"c": @{@".value": @3, @".priority": @1},
     @"d": @{@".value": @4, @".priority": @1},
     @"a": @{@".value": @1, @".priority": @2},
     @"b": @{@".value": @2, @".priority": @2}
     }];

    WAIT_FOR(expectations.isReady);

    [expectations validate];
}

- (void) testStartAtAndEndAtPriorityAndNameWorkWithServerData2 {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];
    __block BOOL ready = NO;
    [ref setValue:@{
     @"c": @{@".value": @3, @".priority": @1},
     @"d": @{@".value": @4, @".priority": @1},
     @"a": @{@".value": @1, @".priority": @2},
     @"b": @{@".value": @2, @".priority": @2}
     } withCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
         ready = YES;
     }];

    WAIT_FOR(ready);

    FTestExpectations* expectations = [[FTestExpectations alloc] initFrom:self];

    FIRDatabaseQuery * query = [[[ref queryOrderedByPriority] queryStartingAtValue:@1 childKey:@"c"] queryEndingAtValue:@2 childKey:@"b"];
    [expectations addQuery:query withExpectation:@{@"a": @1, @"b": @2, @"c": @3, @"d": @4}];

    query = [[[ref queryOrderedByPriority] queryStartingAtValue:@1 childKey:@"d"] queryEndingAtValue:@2 childKey:@"a"];
    [expectations addQuery:query withExpectation:@{@"d": @4, @"a": @1}];

    query = [[[ref queryOrderedByPriority] queryStartingAtValue:@1 childKey:@"e"] queryEndingAtValue:@2];
    [expectations addQuery:query withExpectation:@{@"a": @1, @"b": @2}];

    WAIT_FOR(expectations.isReady);

    [expectations validate];
}

- (void) testEqualToPriorityWorks {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];
    FTestExpectations* expectations = [[FTestExpectations alloc] initFrom:self];

    [expectations addQuery:[[ref queryOrderedByPriority] queryEqualToValue:@"w"] withExpectation:@{@"d": @4}];

    __block id nullSnap = @"dummy";
    [[[ref queryOrderedByPriority] queryEqualToValue:@"c"] observeEventType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
        nullSnap = [snapshot value];
    }];

    [ref setValue:@{
            @"a": @{@".value": @1, @".priority": @"z"},
            @"b": @{@".value": @2, @".priority": @"y"},
            @"c": @{@".value": @3, @".priority": @"x"},
            @"d": @{@".value": @4, @".priority": @"w"}
    }];

    WAIT_FOR(expectations.isReady && [nullSnap isEqual:[NSNull null]]);

    [expectations validate];
}

- (void) testEqualToPriorityWorksWithServerData {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];

    __block BOOL ready = NO;
    [ref setValue:@{
            @"a": @{@".value": @1, @".priority": @"z"},
            @"b": @{@".value": @2, @".priority": @"y"},
            @"c": @{@".value": @3, @".priority": @"x"},
            @"d": @{@".value": @4, @".priority": @"w"}
    } withCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
        ready = YES;
    }];

    WAIT_FOR(ready);

    FTestExpectations* expectations = [[FTestExpectations alloc] initFrom:self];

    [expectations addQuery:[[ref queryOrderedByPriority] queryEqualToValue:@"w"] withExpectation:@{@"d": @4}];

    __block id nullSnap = @"dummy";
    [[[ref queryOrderedByPriority] queryEqualToValue:@"c"] observeEventType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
        nullSnap = [snapshot value];
    }];

    WAIT_FOR(expectations.isReady && [nullSnap isEqual:[NSNull null]]);

    [expectations validate];
}

- (void) testEqualToPriorityAndNameWorks {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];
    FTestExpectations* expectations = [[FTestExpectations alloc] initFrom:self];

    FIRDatabaseQuery * query = [[ref queryOrderedByPriority] queryEqualToValue:@1 childKey:@"a"];
    [expectations addQuery:query withExpectation:@{@"a": @1}];

    __block id nullSnap = @"dummy";
    [[[ref queryOrderedByPriority] queryEqualToValue:@"1" childKey:@"z"] observeEventType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
        nullSnap = [snapshot value];
    }];

    [ref setValue:@{
            @"a": @{@".value": @1, @".priority": @1},
            @"b": @{@".value": @2, @".priority": @1},
            @"c": @{@".value": @3, @".priority": @2},
            @"d": @{@".value": @4, @".priority": @2}
    }];

    WAIT_FOR(expectations.isReady && [nullSnap isEqual:[NSNull null]]);

    [expectations validate];
}

- (void) testEqualToPriorityAndNameWorksWithServerData {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];
    __block BOOL ready = NO;
    [ref setValue:@{
            @"a": @{@".value": @1, @".priority": @1},
            @"b": @{@".value": @2, @".priority": @1},
            @"c": @{@".value": @3, @".priority": @2},
            @"d": @{@".value": @4, @".priority": @2}
    } withCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
        ready = YES;
    }];

    WAIT_FOR(ready);

    FTestExpectations* expectations = [[FTestExpectations alloc] initFrom:self];

    FIRDatabaseQuery * query = [[ref queryOrderedByPriority] queryEqualToValue:@1 childKey:@"a"];
    [expectations addQuery:query withExpectation:@{@"a": @1}];

    __block id nullSnap = @"dummy";
    [[[ref queryOrderedByPriority] queryEqualToValue:@"1" childKey:@"z"] observeEventType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
        nullSnap = [snapshot value];
    }];

    WAIT_FOR(expectations.isReady && [nullSnap isEqual:[NSNull null]]);

    [expectations validate];
}

- (void) testPrevNameWorks {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];

    NSMutableArray* added = [[NSMutableArray alloc] init];

    [[ref queryLimitedToLast:2] observeEventType:FIRDataEventTypeChildAdded andPreviousSiblingKeyWithBlock:^(FIRDataSnapshot *snapshot, NSString *prevName) {
        [added addObject:snapshot.key];
        if (prevName) {
            [added addObject:prevName];
        } else {
            [added addObject:@"null"];
        }

    }];

    [[ref child:@"a"] setValue:@1];
    [self waitUntil:^BOOL{
        NSArray* expected = @[@"a", @"null"];
        return [added isEqualToArray:expected];
    }];

    [added removeAllObjects];

    [[ref child:@"c"] setValue:@3];
    [self waitUntil:^BOOL{
        NSArray* expected = @[@"c", @"a"];
        return [added isEqualToArray:expected];
    }];

    [added removeAllObjects];

    [[ref child:@"b"] setValue:@2];
    [self waitUntil:^BOOL{
        NSArray* expected = @[@"b", @"null"];
        return [added isEqualToArray:expected];
    }];

    [added removeAllObjects];

    [[ref child:@"d"] setValue:@3];
    [self waitUntil:^BOOL{
        NSArray* expected = @[@"d", @"c"];
        return [added isEqualToArray:expected];
    }];
}

// Dropping some of the server data tests here, around prevName. They don't really test anything new, and mostly don't even test server data

- (void) testPrevNameWorksWithMoves {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];

    NSMutableArray* moved = [[NSMutableArray alloc] init];

    [[ref queryLimitedToLast:2] observeEventType:FIRDataEventTypeChildMoved andPreviousSiblingKeyWithBlock:^(FIRDataSnapshot *snapshot, NSString *prevName) {
        [moved addObject:snapshot.key];
        if (prevName) {
            [moved addObject:prevName];
        } else {
            [moved addObject:@"null"];
        }
    }];

    [ref setValue:@{
     @"a": @{@".value": @"a", @".priority": @10},
     @"b": @{@".value": @"b", @".priority": @20},
     @"c": @{@".value": @"c", @".priority": @30},
     @"d": @{@".value": @"d", @".priority": @40}
     }];

    __block BOOL ready = NO;
    [[ref child:@"c"] setPriority:@50 withCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
        ready = YES;
    }];

    [self waitUntil:^BOOL{
        return ready;
    }];

    NSArray* expected = @[@"c", @"d"];
    XCTAssertTrue([moved isEqualToArray:expected], @"Expected changed node and prevChild");

    [moved removeAllObjects];
    ready = NO;
    [[ref child:@"c"] setPriority:@35 withCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
        ready = YES;
    }];

    [self waitUntil:^BOOL{
        return ready;
    }];

    expected = @[@"c", @"null"];
    XCTAssertTrue([moved isEqualToArray:expected], @"Expected changed node and prevChild");

    [moved removeAllObjects];
    ready = NO;
    [[ref child:@"b"] setPriority:@33 withCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
        ready = YES;
    }];

    [self waitUntil:^BOOL{
        return ready;
    }];

    expected = @[];
    XCTAssertTrue([moved isEqualToArray:expected], @"Expected changed node and prevChild to be empty");
}

- (void) testLocalEvents {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];

    NSMutableArray* events = [[NSMutableArray alloc] init];
    [[ref queryLimitedToLast:2] observeEventType:FIRDataEventTypeChildAdded withBlock:^(FIRDataSnapshot *snapshot) {
        NSString *eventString = [NSString stringWithFormat:@"%@ added", [snapshot value]];
        [events addObject:eventString];
    }];

    [[ref queryLimitedToLast:2] observeEventType:FIRDataEventTypeChildRemoved withBlock:^(FIRDataSnapshot *snapshot) {
        NSString *eventString = [NSString stringWithFormat:@"%@ removed", [snapshot value]];
        [events addObject:eventString];
    }];

    __block BOOL ready = NO;
    for (int i = 0; i < 5; ++i) {
        [[ref childByAutoId] setValue:[NSNumber numberWithInt:i] withCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
            if (i == 4) {
                ready = YES;
            }
        }];
    }

    [self waitUntil:^BOOL{
        return ready;
    }];

    NSArray* expected = @[@"0 added", @"1 added", @"0 removed", @"2 added", @"1 removed", @"3 added", @"2 removed", @"4 added"];
    XCTAssertTrue([events isEqualToArray:expected], @"Expecting window to stay at two nodes");
}

- (void) testRemoteEvents {
    FTupleFirebase* pair = [FTestHelpers getRandomNodePair];
    FIRDatabaseReference * writer = pair.one;
    FIRDatabaseReference * reader = pair.two;

    NSMutableArray* events = [[NSMutableArray alloc] init];

    [[reader queryLimitedToLast:2] observeEventType:FIRDataEventTypeChildAdded withBlock:^(FIRDataSnapshot *snapshot) {
        NSString *eventString = [NSString stringWithFormat:@"%@ added", [snapshot value]];
        [events addObject:eventString];
    }];

    [[reader queryLimitedToLast:2] observeEventType:FIRDataEventTypeChildRemoved withBlock:^(FIRDataSnapshot *snapshot) {
        NSString *oldEventString = [NSString stringWithFormat:@"%@ added", [snapshot value]];
        [events removeObject:oldEventString];
    }];

    for (int i = 0; i < 5; ++i) {
        [[writer childByAutoId] setValue:[NSNumber numberWithInt:i]];
    }

    NSArray* expected = @[@"3 added", @"4 added"];
    [self waitUntil:^BOOL{
        return [events isEqualToArray:expected];
    }];
}

- (void) testLimitOnEmptyNodeFiresValue {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];

    __block BOOL ready = NO;
    [[ref queryLimitedToLast:1] observeEventType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
        ready = YES;
    }];

    [self waitUntil:^BOOL{
        return ready;
    }];
}

- (void) testFilteringToNullPriorities {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];

    // Note: cannot set nil in a dictionary, just leave out priority
    [ref setValue:@{
     @"a": @0,
     @"b": @1,
     @"c": @{@".priority": @2, @".value": @2},
     @"d": @{@".priority": @3, @".value": @3},
     @"e": @{@".priority": @"hi", @".value": @4}
     }];

    __block BOOL ready = NO;
    [[[[ref queryOrderedByPriority] queryStartingAtValue:nil] queryEndingAtValue:nil] observeEventType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
        NSDictionary *expected = @{@"a" : @0, @"b" : @1};
        NSDictionary *val = [snapshot value];
        XCTAssertTrue([val isEqualToDictionary:expected], @"Expected only null priority keys");
        ready = YES;
    }];

    [self waitUntil:^BOOL{
        return ready;
    }];
}

- (void) testNullPrioritiesIncludedInEndAt {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];

    // Note: cannot set nil in a dictionary, just leave out priority
    [ref setValue:@{
     @"a": @0,
     @"b": @1,
     @"c": @{@".priority": @2, @".value": @2},
     @"d": @{@".priority": @3, @".value": @3},
     @"e": @{@".priority": @"hi", @".value": @4}
     }];

    __block BOOL ready = NO;
    [[[ref queryOrderedByPriority] queryEndingAtValue:@2] observeEventType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
        NSDictionary *expected = @{@"a" : @0, @"b" : @1, @"c" : @2};
        NSDictionary *val = [snapshot value];
        XCTAssertTrue([val isEqualToDictionary:expected], @"Expected up to priority 2");
        ready = YES;
    }];

    [self waitUntil:^BOOL{
        return ready;
    }];
}

- (NSSet *) dumpListensForRef:(FIRDatabaseReference *)ref {
    NSMutableSet* dumpPieces = [[NSMutableSet alloc] init];
    NSDictionary* listens = [ref.repo dumpListens];

    FPath* nodePath = ref.path;
    [listens enumerateKeysAndObjectsUsingBlock:^(FQuerySpec *spec, id obj, BOOL *stop) {
        if ([nodePath contains:spec.path]) {
            FPath *relative = [FPath relativePathFrom:nodePath to:spec.path];
            [dumpPieces addObject:[[FQuerySpec alloc] initWithPath:relative params:spec.params]];
        }
    }];

    return dumpPieces;
}

- (NSSet *) expectDefaultListenerAtPath:(FPath *)path {
    return [self expectParams:[FQueryParams defaultInstance] atPath:path];
}

- (NSSet *) expectParamssetValue:(NSSet *)paramsSet atPath:(FPath *)path {
    NSMutableSet *all = [NSMutableSet set];
    [paramsSet enumerateObjectsUsingBlock:^(FQueryParams *params, BOOL *stop) {
        [all addObject:[[FQuerySpec alloc] initWithPath:path params:params]];
    }];
    return all;
}

- (NSSet *) expectParams:(FQueryParams *)params atPath:(FPath *)path {
    return [self expectParamssetValue:[NSSet setWithObject:params] atPath:path];
}

- (void) testDedupesListensOnChild {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];
    __block NSSet* listens = [self dumpListensForRef:ref];
    XCTAssertTrue(listens.count == 0, @"No Listens yet");

    [[ref child:@"a"] observeEventType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
    }];
    __block BOOL ready = NO;
    dispatch_async([FIRDatabaseQuery sharedQueue], ^{
        listens = [self dumpListensForRef:ref];
        NSSet* expected = [NSSet setWithObject:[FQuerySpec defaultQueryAtPath:PATH(@"a")]];
        XCTAssertTrue([expected isEqualToSet:listens], @"Expected child listener");
        ready = YES;
    });

    [self waitUntil:^BOOL{
        return ready;
    }];

    [ref observeEventType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
    }];
    ready = NO;
    dispatch_async([FIRDatabaseQuery sharedQueue], ^{
        listens = [self dumpListensForRef:ref];
        NSSet* expected = [NSSet setWithObject:[FQuerySpec defaultQueryAtPath:PATH(@"")]];
        XCTAssertTrue([expected isEqualToSet:listens], @"Expected parent listener");
        ready = YES;
    });

    [self waitUntil:^BOOL{
        return ready;
    }];

    [ref removeAllObservers];
    ready = NO;
    dispatch_async([FIRDatabaseQuery sharedQueue], ^{
        listens = [self dumpListensForRef:ref];
        NSSet* expected = [NSSet setWithObject:[FQuerySpec defaultQueryAtPath:PATH(@"a")]];
        XCTAssertTrue([expected isEqualToSet:listens], @"Child listener should be back");
        ready = YES;
    });

    [self waitUntil:^BOOL{
        return ready;
    }];

    [[ref child:@"a"] removeAllObservers];
    ready = NO;
    dispatch_async([FIRDatabaseQuery sharedQueue], ^{
        listens = [self dumpListensForRef:ref];
        XCTAssertTrue(listens.count == 0, @"No more listeners");
        ready = YES;
    });

    [self waitUntil:^BOOL{
        return ready;
    }];
}

- (void) testDedupeListensOnGrandchild {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];
    __block NSSet* listens;
    __block BOOL ready = NO;
    dispatch_async([FIRDatabaseQuery sharedQueue], ^{
        listens = [self dumpListensForRef:ref];
        XCTAssertTrue(listens.count == 0, @"No Listens yet");
        ready = YES;
    });
    WAIT_FOR(ready);

    [ref observeEventType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
    }];

    dispatch_async([FIRDatabaseQuery sharedQueue], ^{
        listens = [self dumpListensForRef:ref];
        NSSet* expected = [self expectDefaultListenerAtPath:[FPath empty]];
        XCTAssertTrue([expected isEqualToSet:listens], @"Expected one listener");
        ready = YES;
    });
    WAIT_FOR(ready);

    [[ref child:@"a/aa"] observeEventType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
    }];
    ready = NO;
    dispatch_async([FIRDatabaseQuery sharedQueue], ^{
        listens = [self dumpListensForRef:ref];
        NSSet* expected = [self expectDefaultListenerAtPath:[FPath empty]];
        XCTAssertTrue([expected isEqualToSet:listens], @"Expected parent listener to override");
        ready = YES;
    });
    WAIT_FOR(ready);

    [ref removeAllObservers];
    [[ref child:@"a/aa"] removeAllObservers];
    ready = NO;
    dispatch_async([FIRDatabaseQuery sharedQueue], ^{
        listens = [self dumpListensForRef:ref];
        XCTAssertTrue(listens.count == 0, @"No more listeners");
        ready = YES;
    });
    WAIT_FOR(ready);
}

- (void) testListenOnGrandparentOfTwoChildren {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];
    __block NSSet* listens = [self dumpListensForRef:ref];
    XCTAssertTrue(listens.count == 0, @"No Listens yet");

    [[ref child:@"a/aa"] observeEventType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
    }];
    __block BOOL ready = NO;
    dispatch_async([FIRDatabaseQuery sharedQueue], ^{
        listens = [self dumpListensForRef:ref];
        NSSet* expected = [self expectDefaultListenerAtPath:[FPath pathWithString:@"/a/aa"]];
        XCTAssertTrue([expected isEqualToSet:listens], @"Expected grandchild");
        ready = YES;
    });

    [self waitUntil:^BOOL{
        return ready;
    }];

    [[ref child:@"a/bb"] observeEventType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
    }];
    ready = NO;
    dispatch_async([FIRDatabaseQuery sharedQueue], ^{
        listens = [self dumpListensForRef:ref];
        NSSet* expecteda = [self expectDefaultListenerAtPath:[FPath pathWithString:@"/a/aa"]];
        NSSet* expectedb = [self expectDefaultListenerAtPath:[FPath pathWithString:@"/a/bb"]];
        NSMutableSet* expected = [NSMutableSet setWithSet:expecteda];
        [expected unionSet:expectedb];
        XCTAssertTrue([expected isEqualToSet:listens], @"Expected two grandchildren");
        ready = YES;
    });

    [self waitUntil:^BOOL{
        return ready;
    }];

    [ref observeEventType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
    }];
    ready = NO;
    dispatch_async([FIRDatabaseQuery sharedQueue], ^{
        listens = [self dumpListensForRef:ref];
        NSSet* expected = [self expectDefaultListenerAtPath:[FPath empty]];
        XCTAssertTrue([expected isEqualToSet:listens], @"Expected parent listener to override");
        ready = YES;
    });

    [self waitUntil:^BOOL{
        return ready;
    }];

    [ref removeAllObservers];
    ready = NO;
    dispatch_async([FIRDatabaseQuery sharedQueue], ^{
        listens = [self dumpListensForRef:ref];
        NSSet* expecteda = [self expectDefaultListenerAtPath:[FPath pathWithString:@"/a/aa"]];
        NSSet* expectedb = [self expectDefaultListenerAtPath:[FPath pathWithString:@"/a/bb"]];
        NSMutableSet* expected = [NSMutableSet setWithSet:expecteda];
        [expected unionSet:expectedb];
        XCTAssertTrue([expected isEqualToSet:listens], @"Expected grandchild listeners to return");
        ready = YES;
    });

    [self waitUntil:^BOOL{
        return ready;
    }];

    [[ref child:@"a/aa"] removeAllObservers];
    ready = NO;
    dispatch_async([FIRDatabaseQuery sharedQueue], ^{
        listens = [self dumpListensForRef:ref];
        NSSet* expected = [self expectDefaultListenerAtPath:[FPath pathWithString:@"/a/bb"]];
        XCTAssertTrue([expected isEqualToSet:listens], @"Expected one listener");
        ready = YES;
    });

    [self waitUntil:^BOOL{
        return ready;
    }];

    [[ref child:@"a/bb"] removeAllObservers];
    ready = NO;
    dispatch_async([FIRDatabaseQuery sharedQueue], ^{
        listens = [self dumpListensForRef:ref];
        XCTAssertTrue(listens.count == 0, @"No more listeners");
        ready = YES;
    });

    [self waitUntil:^BOOL{
        return ready;
    }];
}

- (void) testDedupingMultipleListenQueries {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];
    __block NSSet* listens = [self dumpListensForRef:ref];
    XCTAssertTrue(listens.count == 0, @"No Listens yet");

    __block BOOL ready = NO;
    FIRDatabaseQuery * aLim1 = [[ref child:@"a"] queryLimitedToLast:1];
    FIRDatabaseHandle handle1 = [aLim1 observeEventType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
    }];
    dispatch_async([FIRDatabaseQuery sharedQueue], ^{
        listens = [self dumpListensForRef:ref];
        FQueryParams* expectedParams = [[FQueryParams alloc] init];
        expectedParams = [expectedParams limitTo:1];
        NSSet* expected = [self expectParams:expectedParams atPath:[FPath pathWithString:@"/a"]];
        XCTAssertTrue([expected isEqualToSet:listens], @"Single query");
        ready = YES;
    });

    [self waitUntil:^BOOL{
        return ready;
    }];

    ready = NO;
    FIRDatabaseQuery * rootLim1 = [ref queryLimitedToLast:1];
    FIRDatabaseHandle handle2 = [rootLim1 observeEventType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
    }];
    dispatch_async([FIRDatabaseQuery sharedQueue], ^{
        listens = [self dumpListensForRef:ref];
        FQueryParams* expectedParams = [[FQueryParams alloc] init];
        expectedParams = [expectedParams limitTo:1];
        NSSet* rootExpected = [self expectParams:expectedParams atPath:[FPath empty]];
        NSSet* childExpected = [self expectParams:expectedParams atPath:[FPath pathWithString:@"/a"]];
        NSMutableSet* expected = [NSMutableSet setWithSet:rootExpected];
        [expected unionSet:childExpected];
        XCTAssertTrue([expected isEqualToSet:listens], @"Two queries");
        ready = YES;
    });

    [self waitUntil:^BOOL{
        return ready;
    }];

    ready = NO;
    FIRDatabaseQuery * aLim5 = [[ref child:@"a"] queryLimitedToLast:5];
    FIRDatabaseHandle handle3 = [aLim5 observeEventType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
    }];
    dispatch_async([FIRDatabaseQuery sharedQueue], ^{
        listens = [self dumpListensForRef:ref];
        FQueryParams* expectedParams1 = [[FQueryParams alloc] init];
        expectedParams1 = [expectedParams1 limitTo:1];
        NSSet* rootExpected = [self expectParams:expectedParams1 atPath:[FPath empty]];

        FQueryParams* expectedParams2 = [[FQueryParams alloc] init];
        expectedParams2 = [expectedParams2 limitTo:5];
        NSSet* childExpected = [self expectParamssetValue:[NSSet setWithObjects:expectedParams1, expectedParams2, nil] atPath:[FPath pathWithString:@"/a"]];
        NSMutableSet* expected = [NSMutableSet setWithSet:childExpected];
        [expected unionSet:rootExpected];
        XCTAssertTrue([expected isEqualToSet:listens], @"Three queries");
        ready = YES;
    });

    [self waitUntil:^BOOL{
        return ready;
    }];

    [ref removeObserverWithHandle:handle2];
    ready = NO;
    dispatch_async([FIRDatabaseQuery sharedQueue], ^{
        listens = [self dumpListensForRef:ref];
        FQueryParams* expectedParams1 = [[FQueryParams alloc] init];
        expectedParams1 = [expectedParams1 limitTo:1];
        FQueryParams* expectedParams2 = [[FQueryParams alloc] init];
        expectedParams2= [expectedParams2 limitTo:5];
        NSSet* expected = [self expectParamssetValue:[NSSet setWithObjects:expectedParams1, expectedParams2, nil] atPath:[FPath pathWithString:@"/a"]];
        XCTAssertTrue([expected isEqualToSet:listens], @"Two queries");
        ready = YES;
    });

    [self waitUntil:^BOOL{
        return ready;
    }];

    [aLim1 removeObserverWithHandle:handle1];
    [aLim5 removeObserverWithHandle:handle3];
    ready = NO;
    dispatch_async([FIRDatabaseQuery sharedQueue], ^{
        listens = [self dumpListensForRef:ref];
        XCTAssertTrue(listens.count == 0, @"No more listeners");
        ready = YES;
    });

    [self waitUntil:^BOOL{
        return ready;
    }];
}

- (void) testListenOnParentOfQueriedChildren {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];
    __block NSSet* listens = [self dumpListensForRef:ref];
    XCTAssertTrue(listens.count == 0, @"No Listens yet");

    __block BOOL ready = NO;
    FIRDatabaseQuery * aLim1 = [[ref child:@"a"] queryLimitedToLast:1];
    FIRDatabaseHandle handle1 = [aLim1 observeEventType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
    }];
    dispatch_async([FIRDatabaseQuery sharedQueue], ^{
        listens = [self dumpListensForRef:ref];
        FQueryParams* expectedParams = [[FQueryParams alloc] init];
        expectedParams = [expectedParams limitTo:1];
        NSSet* expected = [self expectParams:expectedParams atPath:[FPath pathWithString:@"/a"]];
        XCTAssertTrue([expected isEqualToSet:listens], @"Single query");
        ready = YES;
    });

    [self waitUntil:^BOOL{
        return ready;
    }];

    ready = NO;
    FIRDatabaseQuery * bLim1 = [[ref child:@"b"] queryLimitedToLast:1];
    FIRDatabaseHandle handle2 = [bLim1 observeEventType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
    }];
    dispatch_async([FIRDatabaseQuery sharedQueue], ^{
        listens = [self dumpListensForRef:ref];
        FQueryParams* expectedParams = [[FQueryParams alloc] init];
        expectedParams = [expectedParams limitTo:1];
        NSSet* expecteda = [self expectParams:expectedParams atPath:[FPath pathWithString:@"/a"]];
        NSSet* expectedb = [self expectParams:expectedParams atPath:[FPath pathWithString:@"/b"]];
        NSMutableSet* expected = [NSMutableSet setWithSet:expecteda];
        [expected unionSet:expectedb];
        XCTAssertTrue([expected isEqualToSet:listens], @"Two queries");
        ready = YES;
    });

    [self waitUntil:^BOOL{
        return ready;
    }];

    ready = NO;
    FIRDatabaseHandle handle3 = [ref observeEventType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
    }];
    dispatch_async([FIRDatabaseQuery sharedQueue], ^{
        listens = [self dumpListensForRef:ref];
        NSSet* expected = [self expectDefaultListenerAtPath:[FPath empty]];
        XCTAssertTrue([expected isEqualToSet:listens], @"Parent should override");
        ready = YES;
    });

    [self waitUntil:^BOOL{
        return ready;
    }];

    // remove in slightly random order
    [aLim1 removeObserverWithHandle:handle1];
    ready = NO;
    dispatch_async([FIRDatabaseQuery sharedQueue], ^{
        listens = [self dumpListensForRef:ref];
        NSSet* expected = [self expectDefaultListenerAtPath:[FPath empty]];
        XCTAssertTrue([expected isEqualToSet:listens], @"Parent should override");
        ready = YES;
    });

    [self waitUntil:^BOOL{
        return ready;
    }];

    [ref removeObserverWithHandle:handle3];
    ready = NO;
    dispatch_async([FIRDatabaseQuery sharedQueue], ^{
        listens = [self dumpListensForRef:ref];
        FQueryParams* expectedParams = [[FQueryParams alloc] init];
        expectedParams = [expectedParams limitTo:1];
        NSSet* expected = [self expectParams:expectedParams atPath:[FPath pathWithString:@"/b"]];
        XCTAssertTrue([expected isEqualToSet:listens], @"Single query");
        ready = YES;
    });

    [self waitUntil:^BOOL{
        return ready;
    }];

    ready = NO;
    [bLim1 removeObserverWithHandle:handle2];
    dispatch_async([FIRDatabaseQuery sharedQueue], ^{
        listens = [self dumpListensForRef:ref];
        XCTAssertTrue(listens.count == 0, @"No more listeners");
        ready = YES;
    });

    [self waitUntil:^BOOL{
        return ready;
    }];
}

-(void) testLimitWithMixOfNullAndNonNullPriorities {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];

    NSMutableArray* children = [[NSMutableArray alloc] init];

    [[ref queryLimitedToLast:5] observeEventType:FIRDataEventTypeChildAdded withBlock:^(FIRDataSnapshot *snapshot) {
        [children addObject:[snapshot key]];
    }];

    __block BOOL ready = NO;
    NSDictionary* toSet = @{
    @"Vikrum": @{@".priority": @1000, @"score": @1000, @"name": @"Vikrum"},
    @"Mike": @{@".priority": @500, @"score": @500, @"name": @"Mike"},
    @"Andrew": @{@".priority": @50, @"score": @50, @"name": @"Andrew"},
    @"James": @{@".priority": @7, @"score": @7, @"name": @"James"},
    @"Sally": @{@".priority": @-7, @"score": @-7, @"name": @"Sally"},
    @"Fred": @{@"score": @0, @"name": @"Fred"}
    };

    [ref setValue:toSet withCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
        ready = YES;
    }];

    [self waitUntil:^BOOL{
        return ready;
    }];

    NSArray* expected = @[@"Sally", @"James", @"Andrew", @"Mike", @"Vikrum"];
    XCTAssertTrue([children isEqualToArray:expected], @"Null priority should be left out");

}

-(void) testLimitWithMixOfNullAndNonNullPrioritiesOnServerData {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];

    __block BOOL ready = NO;
    NSDictionary* toSet = @{
    @"Vikrum": @{@".priority": @1000, @"score": @1000, @"name": @"Vikrum"},
    @"Mike": @{@".priority": @500, @"score": @500, @"name": @"Mike"},
    @"Andrew": @{@".priority": @50, @"score": @50, @"name": @"Andrew"},
    @"James": @{@".priority": @7, @"score": @7, @"name": @"James"},
    @"Sally": @{@".priority": @-7, @"score": @-7, @"name": @"Sally"},
    @"Fred": @{@"score": @0, @"name": @"Fred"}
    };

    [ref setValue:toSet withCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
        ready = YES;
    }];

    [self waitUntil:^BOOL{
        return ready;
    }];

    __block int count = 0;
    NSMutableArray* children = [[NSMutableArray alloc] init];

    [[ref queryLimitedToLast:5] observeEventType:FIRDataEventTypeChildAdded withBlock:^(FIRDataSnapshot *snapshot) {
        [children addObject:[snapshot key]];
        count++;
    }];

    [self waitUntil:^BOOL{
        return count == 5;
    }];


    NSArray* expected = @[@"Sally", @"James", @"Andrew", @"Mike", @"Vikrum"];
    XCTAssertTrue([children isEqualToArray:expected], @"Null priority should be left out");

}

// Skipping context tests. Context is not implemented on iOS

/* DISABLING for now, since I'm not 100% sure what the right behavior is.
   Perhaps a merge at /foo should shadow server updates at /foo instead of
   just the modified children?  Not sure.
- (void) testHandleUpdateThatDeletesEntireWindow {
    Firebase* ref = [FTestHelpers getRandomNode];

    NSMutableArray* snaps = [[NSMutableArray alloc] init];

    [[ref queryLimitedToLast:2] observeEventType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
        id val = [snapshot value];
        if (val == nil) {
            [snaps addObject:[NSNull null]];
        } else {
            [snaps addObject:val];
        }
    }];

    NSDictionary* toSet = @{
    @"a": @{@".priority": @1, @".value": @1},
    @"b": @{@".priority": @2, @".value": @2},
    @"c": @{@".priority": @3, @".value": @3}
    };

    [ref setValue:toSet];

    __block BOOL ready = NO;
    toSet = @{@"b": [NSNull null], @"c": [NSNull null]};
    [ref updateChildValues:toSet withCompletionBlock:^(NSError* err, Firebase* ref) {
        ready = YES;
    }];

    [self waitUntil:^BOOL{
        return ready;
    }];

    NSArray* expected = @[@{@"b": @2, @"c": @3}, [NSNull null], @{@"a": @1}];
    STAssertTrue([snaps isEqualToArray:expected], @"Expected %@ to equal %@", snaps, expected);
}
*/

- (void) testHandlesAnOutOfViewQueryOnAChild {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];

    __block NSDictionary* parent = nil;
    [[ref queryLimitedToLast:1] observeEventType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
        parent = [snapshot value];
    }];

    __block NSNumber* child = nil;
    [[ref child:@"a"] observeEventType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
        child = [snapshot value];
    }];

    __block BOOL ready = NO;
    NSDictionary* toSet = @{@"a": @1, @"b": @2};
    [ref setValue:toSet withCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
        ready = YES;
    }];

    [self waitUntil:^BOOL{
        return ready;
    }];

    NSDictionary* parentExpected = @{@"b": @2};
    NSNumber* childExpected = [NSNumber numberWithInt:1];
    XCTAssertTrue([parent isEqualToDictionary:parentExpected], @"Expected last element");
    XCTAssertTrue([child isEqualToNumber:childExpected], @"Expected value of a");

    ready = NO;
    [ref updateChildValues:@{@"c": @3} withCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
        ready = YES;
    }];

    [self waitUntil:^BOOL{
        return ready;
    }];

    parentExpected = @{@"c": @3};
    XCTAssertTrue([parent isEqualToDictionary:parentExpected], @"Expected last element");
    XCTAssertTrue([child isEqualToNumber:childExpected], @"Expected value of a");
}

- (void) testHandlesAChildQueryGoingOutOfViewOfTheParent {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];

    __block NSDictionary* parent = nil;
    [[ref queryLimitedToLast:1] observeEventType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
        parent = [snapshot value];
    }];

    __block NSNumber* child = nil;
    [[ref child:@"a"] observeEventType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
        child = [snapshot value];
    }];

    __block BOOL ready = NO;
    NSDictionary* toSet = @{@"a": @1};
    [ref setValue:toSet withCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
        ready = YES;
    }];

    WAIT_FOR(ready);

    NSDictionary* parentExpected = @{@"a": @1};
    NSNumber* childExpected = [NSNumber numberWithInt:1];
    XCTAssertTrue([parent isEqualToDictionary:parentExpected], @"Expected last element");
    XCTAssertTrue([child isEqualToNumber:childExpected], @"Expected value of a");

    ready = NO;
    [[ref child:@"b"] setValue:@2 withCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
        ready = YES;
    }];

    WAIT_FOR(ready);

    parentExpected = @{@"b": @2};
    XCTAssertTrue([parent isEqualToDictionary:parentExpected], @"Expected last element");
    XCTAssertTrue([child isEqualToNumber:childExpected], @"Expected value of a");

    ready = NO;
    [[ref child:@"b"] removeValueWithCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
        ready = YES;
    }];

    [self waitUntil:^BOOL{
        return ready;
    }];

    parentExpected = @{@"a": @1};
    XCTAssertTrue([parent isEqualToDictionary:parentExpected], @"Expected last element");
    XCTAssertTrue([child isEqualToNumber:childExpected], @"Expected value of a");
}

- (void) testHandlesDivergingViews {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];

    __block NSDictionary* cVal = nil;
    FIRDatabaseQuery * query = [[[ref queryOrderedByPriority] queryEndingAtValue:nil childKey:@"c"] queryLimitedToLast:1];
    [query observeEventType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
        cVal = [snapshot value];
    }];

    __block NSDictionary* dVal = nil;
    query = [[[ref queryOrderedByPriority] queryEndingAtValue:nil childKey:@"d"] queryLimitedToLast:1];
    [query observeEventType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
        dVal = [snapshot value];
    }];

    __block BOOL ready = NO;
    NSDictionary* toSet = @{@"a": @1, @"b": @2, @"c": @3};
    [ref setValue:toSet withCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
        ready = YES;
    }];

    [self waitUntil:^BOOL{
        return ready;
    }];

    NSDictionary* expected = @{@"c": @3};
    XCTAssertTrue([cVal isEqualToDictionary:expected], @"should be c");
    XCTAssertTrue([dVal isEqualToDictionary:expected], @"should be c");

    ready = NO;
    [[ref child:@"d"] setValue:@4 withCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
        ready = YES;
    }];

    [self waitUntil:^BOOL{
        return ready;
    }];

    XCTAssertTrue([cVal isEqualToDictionary:expected], @"should be c");
    expected = @{@"d": @4};
    XCTAssertTrue([dVal isEqualToDictionary:expected], @"should be d");
}

- (void) testHandlesRemovingAQueriedElement {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];

    __block NSNumber* val = nil;
    [[ref queryLimitedToLast:1] observeEventType:FIRDataEventTypeChildAdded withBlock:^(FIRDataSnapshot *snapshot) {
        id newVal = [snapshot value];
        if (newVal != nil) {
            val = [snapshot value];
        }
    }];

    __block BOOL ready = NO;
    [ref setValue:@{@"a": @1, @"b": @2} withCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
        ready = YES;
    }];

    [self waitUntil:^BOOL{
        return ready;
    }];

    XCTAssertTrue([val isEqualToNumber:@2], @"Expected last element in window");

    ready = NO;
    [[ref child:@"b"] removeValueWithCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
        ready = YES;
    }];

    [self waitUntil:^BOOL{
        return ready;
    }];

    XCTAssertTrue([val isEqualToNumber:@1], @"Should now be the next element in the window");
}

- (void) testStartAtAndLimit1Works {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];

    __block NSNumber* val = nil;
    FIRDatabaseQuery * query = [[[ref queryOrderedByPriority] queryStartingAtValue:nil] queryLimitedToFirst:1];
    [query observeEventType:FIRDataEventTypeChildAdded withBlock:^(FIRDataSnapshot *snapshot) {
        id newVal = [snapshot value];
        if (newVal != nil) {
            val = [snapshot value];
        }
    }];

    __block BOOL ready = NO;
    [ref setValue:@{@"a": @1, @"b": @2} withCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
        ready = YES;
    }];

    [self waitUntil:^BOOL{
        return ready;
    }];

    XCTAssertTrue([val isEqualToNumber:@1], @"Expected first element in window");
}

// See case 1664
- (void) testStartAtAndLimit1AndRemoveFirstChild {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];

    __block NSNumber* val = nil;
    FIRDatabaseQuery * query = [[[ref queryOrderedByPriority] queryStartingAtValue:nil] queryLimitedToFirst:1];
    [query observeEventType:FIRDataEventTypeChildAdded withBlock:^(FIRDataSnapshot *snapshot) {
        id newVal = [snapshot value];
        if (newVal != nil) {
            val = [snapshot value];
        }
    }];

    __block BOOL ready = NO;
    [ref setValue:@{@"a": @1, @"b": @2} withCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
        ready = YES;
    }];

    [self waitUntil:^BOOL{
        return ready;
    }];

    XCTAssertTrue([val isEqualToNumber:@1], @"Expected first element in window");

    ready = NO;
    [[ref child:@"a"] removeValueWithCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
        ready = YES;
    }];

    [self waitUntil:^BOOL{
        return ready;
    }];

    XCTAssertTrue([val isEqualToNumber:@2], @"Expected next element in window");
}

// See case 1169
- (void) testStartAtWithTwoArgumentsWorks {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];

    __block BOOL ready = NO;
    NSMutableArray* children = [[NSMutableArray alloc] init];

    NSDictionary* toSet = @{
    @"Walker": @{@"name": @"Walker", @"score": @20, @".priority": @20},
    @"Michael": @{@"name": @"Michael", @"score": @100, @".priority": @100}
    };

    [ref setValue:toSet withCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
        ready = YES;
    }];

    [self waitUntil:^BOOL{
        return ready;
    }];

    ready = NO;
    FIRDatabaseQuery * query = [[[ref queryOrderedByPriority] queryStartingAtValue:@20 childKey:@"Walker"] queryLimitedToFirst:2];
    [query observeEventType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {

        for (FIRDataSnapshot *child in snapshot.children) {
            [children addObject:child.key];
        }
        ready = YES;
    }];

    [self waitUntil:^BOOL{
        return ready;
    }];

    NSArray* expected = @[@"Walker", @"Michael"];
    XCTAssertTrue([children isEqualToArray:expected], @"Expected both children");
}

- (void) testHandlesMultipleQueriesOnSameNode {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];

    __block BOOL ready = NO;

    NSDictionary* toSet = @{
    @"a": @1, @"b": @2, @"c": @3, @"d": @4, @"e": @5, @"f": @6
    };

    [ref setValue:toSet withCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
        ready = YES;
    }];

    [self waitUntil:^BOOL{
        return ready;
    }];

    ready = NO;
    __block BOOL called = NO;
    [[ref queryLimitedToLast:2] observeEventType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
        // we got the initial data
        XCTAssertFalse(called, @"This should only get called once, we don't update data after this");
        called = YES;
        ready = YES;
    }];

    [self waitUntil:^BOOL{
        return ready;
    }];

    ready = NO;
    __block NSDictionary* snap = nil;
    // now do nested once calls
    [[ref queryLimitedToLast:1] observeSingleEventOfType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
        [[ref queryLimitedToLast:1] observeSingleEventOfType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {

            snap = [snapshot value];
            ready = YES;
        }];
    }];

    [self waitUntil:^BOOL{
        return ready;
    }];

    NSDictionary* expected = @{@"f": @6};
    XCTAssertTrue([snap isEqualToDictionary:expected], @"Expected the correct data");
}

- (void) testHandlesOnceCalledOnNodeWithDefaultListener {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];

    __block BOOL ready = NO;

    NSDictionary* toSet = @{
    @"a": @1, @"b": @2, @"c": @3, @"d": @4, @"e": @5, @"f": @6
    };

    [ref setValue:toSet withCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
        ready = YES;
    }];

    [self waitUntil:^BOOL{
        return ready;
    }];

    ready = NO;

    [ref observeEventType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
        // we got the initial data
        ready = YES;
    }];

    [self waitUntil:^BOOL{
        return ready;
    }];

    ready = NO;

    __block NSNumber* snap = nil;
    [[ref queryLimitedToLast:1] observeSingleEventOfType:FIRDataEventTypeChildAdded withBlock:^(FIRDataSnapshot *snapshot) {
        snap = [snapshot value];
        ready = YES;
    }];

    [self waitUntil:^BOOL{
        return ready;
    }];

    XCTAssertTrue([snap isEqualToNumber:@6], @"Got once response");
}

- (void) testHandlesOnceCalledOnNodeWithDefaultListenerAndNonCompleteLimit {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];

    __block BOOL ready = NO;

    NSDictionary* toSet = @{@"a": @1, @"b": @2, @"c": @3};

    [ref setValue:toSet withCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
        ready = YES;
    }];

    [self waitUntil:^BOOL{
        return ready;
    }];

    ready = NO;
    // do first listen
    [ref observeEventType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
        ready = YES;
    }];

    [self waitUntil:^BOOL{
        return ready;
    }];

    ready = NO;

    __block NSDictionary* snap = nil;
    [[ref queryLimitedToLast:5] observeSingleEventOfType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
        snap = [snapshot value];
        ready = YES;
    }];

    [self waitUntil:^BOOL{
        return ready;
    }];

    NSDictionary* expected = @{@"a": @1, @"b": @2, @"c": @3};
    XCTAssertTrue([snap isEqualToDictionary:expected], @"Got once response");
}

- (void) testRemoveTriggersRemoteEvents {
    FTupleFirebase* tuple = [FTestHelpers getRandomNodePair];
    FIRDatabaseReference * writer = tuple.one;
    FIRDatabaseReference * reader = tuple.two;

    __block BOOL ready = NO;

    NSDictionary* toSet = @{@"a": @"a", @"b": @"b", @"c": @"c", @"d": @"d", @"e": @"e"};

    [writer setValue:toSet withCompletionBlock:^(NSError* err, FIRDatabaseReference * ref) {
        ready = YES;
    }];

    [self waitUntil:^BOOL{
        return ready;
    }];

    ready = NO;
    __block int count = 0;

    [[reader queryLimitedToLast:5] observeEventType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
        count++;
        if (count == 1) {
            NSDictionary *val = [snapshot value];
            NSDictionary *expected = @{@"a" : @"a", @"b" : @"b", @"c" : @"c", @"d" : @"d", @"e" : @"e"};
            XCTAssertTrue([val isEqualToDictionary:expected], @"First callback, expect all the data");
            [[writer child:@"c"] removeValue];
        } else {
            XCTAssertTrue(count == 2, @"Should only get called twice");
            NSDictionary *val = [snapshot value];
            NSDictionary *expected = @{@"a" : @"a", @"b" : @"b", @"d" : @"d", @"e" : @"e"};
            XCTAssertTrue([val isEqualToDictionary:expected], @"Second callback, expect all the remaining data");
            ready = YES;
        }
    }];

    [self waitUntil:^BOOL{
        return ready;
    }];
}

- (void) testEndingAtNameReturnsCorrectChildren {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];

    NSDictionary* toSet = @{
    @"a": @"a",
    @"b": @"b",
    @"c": @"c",
    @"d": @"d",
    @"e": @"e",
    @"f": @"f",
    @"g": @"g",
    @"h": @"h"
    };

    [self waitForCompletionOf:ref setValue:toSet];

    __block NSDictionary* snap = nil;
    __block BOOL done = NO;
    FIRDatabaseQuery * query = [[[ref queryOrderedByPriority] queryEndingAtValue:nil childKey:@"f"] queryLimitedToLast:5];
    [query observeEventType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
        snap = [snapshot value];
        done = YES;
    }];

    [self waitUntil:^BOOL{
        return done;
    }];

    NSDictionary* expected = @{
    @"b": @"b",
    @"c": @"c",
    @"d": @"d",
    @"e": @"e",
    @"f": @"f"
    };
    XCTAssertTrue([snap isEqualToDictionary:expected], @"Expected 5 elements, ending at f");
}

- (void) testListenForChildAddedWithLimitEnsureEventsFireProperly {
    FTupleFirebase* refs = [FTestHelpers getRandomNodePair];
    FIRDatabaseReference * writer = refs.one;
    FIRDatabaseReference * reader = refs.two;

    __block BOOL done = NO;

    NSDictionary* toSet = @{@"a": @1, @"b": @"b", @"c": @{@"deep": @"path", @"of": @{@"stuff": @YES}}};
    [writer setValue:toSet withCompletionBlock:^(NSError* error, FIRDatabaseReference * ref) {
        done = YES;
    }];

    WAIT_FOR(done);

    __block int count = 0;
    [[reader queryLimitedToLast:3] observeEventType:FIRDataEventTypeChildAdded withBlock:^(FIRDataSnapshot *snapshot) {
        count++;
        if (count == 1) {
            XCTAssertTrue([snapshot.key isEqualToString:@"a"], @"Got first child");
            XCTAssertTrue([snapshot.value isEqualToNumber:@1], @"Got correct value");
        } else if (count == 2) {
            XCTAssertTrue([snapshot.key isEqualToString:@"b"], @"Got second child");
            XCTAssertTrue([snapshot.value isEqualToString:@"b"], @"got correct value");
        } else if (count == 3) {
            XCTAssertTrue([snapshot.key isEqualToString:@"c"], @"Got third child");
            NSDictionary *expected = @{@"deep" : @"path", @"of" : @{@"stuff" : @YES}};
            XCTAssertTrue([snapshot.value isEqualToDictionary:expected], @"Got deep object");
        } else {
            XCTFail(@"wrong event count");
        }
    }];

    WAIT_FOR(count == 3);
}


- (void) testListenForChildChangedWithLimitEnsureEventsFireProperly {
    FTupleFirebase* refs = [FTestHelpers getRandomNodePair];
    FIRDatabaseReference * writer = refs.one;
    FIRDatabaseReference * reader = refs.two;

    __block BOOL done = NO;

    NSDictionary* toSet = @{@"a": @"something", @"b": @"we'll", @"c": @"overwrite"};
    [writer setValue:toSet withCompletionBlock:^(NSError* error, FIRDatabaseReference * ref) {
        done = YES;
    }];

    WAIT_FOR(done);

    __block int count = 0;
    [reader observeEventType:FIRDataEventTypeChildChanged withBlock:^(FIRDataSnapshot *snapshot) {
        count++;
        if (count == 1) {
            XCTAssertTrue([snapshot.key isEqualToString:@"a"], @"Got first child");
            XCTAssertTrue([snapshot.value isEqualToNumber:@1], @"Got correct value");
        } else if (count == 2) {
            XCTAssertTrue([snapshot.key isEqualToString:@"b"], @"Got second child");
            XCTAssertTrue([snapshot.value isEqualToString:@"b"], @"got correct value");
        } else if (count == 3) {
            XCTAssertTrue([snapshot.key isEqualToString:@"c"], @"Got third child");
            NSDictionary *expected = @{@"deep" : @"path", @"of" : @{@"stuff" : @YES}};
            XCTAssertTrue([snapshot.value isEqualToDictionary:expected], @"Got deep object");
        } else {
            XCTFail(@"wrong event count");
        }
    }];
    toSet = @{@"a": @1, @"b": @"b", @"c": @{@"deep": @"path", @"of": @{@"stuff": @YES}}};
    [writer setValue:toSet];

    WAIT_FOR(count == 3);
}

- (void) testListenForChildRemovedWithLimitEnsureEventsFireProperly {
    FTupleFirebase* refs = [FTestHelpers getRandomNodePair];
    FIRDatabaseReference * writer = refs.one;
    FIRDatabaseReference * reader = refs.two;

    __block BOOL done = NO;

    NSDictionary* toSet = @{@"a": @1, @"b": @"b", @"c": @{@"deep": @"path", @"of": @{@"stuff": @YES}}};
    [writer setValue:toSet withCompletionBlock:^(NSError* error, FIRDatabaseReference * ref) {
        done = YES;
    }];

    WAIT_FOR(done);

    __block int count = 0;
    [reader observeEventType:FIRDataEventTypeChildRemoved withBlock:^(FIRDataSnapshot *snapshot) {
        count++;
        if (count == 1) {
            XCTAssertTrue([snapshot.key isEqualToString:@"a"], @"Got first child");
            XCTAssertTrue([snapshot.value isEqualToNumber:@1], @"Got correct value");
        } else if (count == 2) {
            XCTAssertTrue([snapshot.key isEqualToString:@"b"], @"Got second child");
            XCTAssertTrue([snapshot.value isEqualToString:@"b"], @"got correct value");
        } else if (count == 3) {
            XCTAssertTrue([snapshot.key isEqualToString:@"c"], @"Got third child");
            NSDictionary *expected = @{@"deep" : @"path", @"of" : @{@"stuff" : @YES}};
            XCTAssertTrue([snapshot.value isEqualToDictionary:expected], @"Got deep object");
        } else {
            XCTFail(@"wrong event count");
        }
    }];

    done = NO;
    [reader observeEventType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
        // Load the data first
        done = snapshot.value != [NSNull null] && [snapshot.value isEqualToDictionary:toSet];
    }];

    WAIT_FOR(done);

    // Now do the removes
    [[writer child:@"a"] removeValue];
    [[writer child:@"b"] removeValue];
    [[writer child:@"c"] removeValue];

    WAIT_FOR(count == 3);
}

- (void) testQueriesBehaveProperlyAfterOnceCall {
    FTupleFirebase* refs = [FTestHelpers getRandomNodePair];
    FIRDatabaseReference * writer = refs.one;
    FIRDatabaseReference * reader = refs.two;

    __block BOOL done = NO;
    NSDictionary* toSet = @{@"a": @1, @"b": @2, @"c": @3, @"d": @4};
    [writer setValue:toSet withCompletionBlock:^(NSError* error, FIRDatabaseReference * ref) {
        done = YES;
    }];

    WAIT_FOR(done);

    done = NO;
    [reader observeSingleEventOfType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
        done = YES;
    }];

    WAIT_FOR(done);

    // Ok, now do some queries
    __block int startCount = 0;
    __block int defaultCount = 0;
    [[[reader queryOrderedByPriority] queryStartingAtValue:nil childKey:@"d"] observeEventType:FIRDataEventTypeChildAdded withBlock:^(FIRDataSnapshot *snapshot) {
        startCount++;
    }];

    [reader observeEventType:FIRDataEventTypeChildAdded withBlock:^(FIRDataSnapshot *snapshot) {
        defaultCount++;
    }];

    [reader observeEventType:FIRDataEventTypeChildRemoved withBlock:^(FIRDataSnapshot *snapshot) {
        XCTFail(@"Should not remove any children");
    }];

    WAIT_FOR(startCount == 1 && defaultCount == 4);
}

- (void) testIntegerKeysBehaveNumerically1 {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];
    NSDictionary* toSet = @{@"1": @YES, @"50": @YES, @"550": @YES, @"6": @YES, @"600": @YES, @"70": @YES, @"8": @YES, @"80": @YES };
    __block BOOL done = NO;
    [ref setValue:toSet withCompletionBlock:^(NSError *error, FIRDatabaseReference *ref) {
        [[[ref queryOrderedByPriority] queryStartingAtValue:nil childKey:@"80"] observeSingleEventOfType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
            NSDictionary *expected = @{@"80" : @YES, @"550" : @YES, @"600" : @YES};
            XCTAssertTrue([snapshot.value isEqualToDictionary:expected], @"Got correct result.");
            done = YES;
        }];
    }];
    WAIT_FOR(done);
}

- (void) testIntegerKeysBehaveNumerically2 {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];
    NSDictionary* toSet = @{@"1": @YES, @"50": @YES, @"550": @YES, @"6": @YES, @"600": @YES, @"70": @YES, @"8": @YES, @"80": @YES };
    __block BOOL done = NO;
    [ref setValue:toSet withCompletionBlock:^(NSError *error, FIRDatabaseReference *ref) {
        [[[ref queryOrderedByPriority] queryEndingAtValue:nil childKey:@"50"] observeSingleEventOfType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
            NSDictionary *expected = @{@"1" : @YES, @"6" : @YES, @"8" : @YES, @"50" : @YES};
            XCTAssertTrue([snapshot.value isEqualToDictionary:expected], @"Got correct result.");
            done = YES;
        }];
    }];
    WAIT_FOR(done);
}

- (void) testIntegerKeysBehaveNumerically3 {
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];
    NSDictionary* toSet = @{@"1": @YES, @"50": @YES, @"550": @YES, @"6": @YES, @"600": @YES, @"70": @YES, @"8": @YES, @"80": @YES };
    __block BOOL done = NO;
    [ref setValue:toSet withCompletionBlock:^(NSError *error, FIRDatabaseReference *ref) {
        [[[[ref queryOrderedByPriority] queryStartingAtValue:nil childKey:@"50"] queryEndingAtValue:nil childKey:@"80"] observeSingleEventOfType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
            NSDictionary *expected = @{@"50" : @YES, @"70" : @YES, @"80" : @YES};
            XCTAssertTrue([snapshot.value isEqualToDictionary:expected], @"Got correct result.");
            done = YES;
        }];
    }];
    WAIT_FOR(done);
}

- (void) testItemsPulledIntoLimitCorrectly {
    FIRDatabaseReference *ref = [FTestHelpers getRandomNode];

    NSMutableArray* snaps = [[NSMutableArray alloc] init];

    // Just so everything is cached locally.
    [ref observeEventType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {

    }];

    [[ref queryLimitedToLast:2] observeEventType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
        id val = [snapshot value];
        [snaps addObject:val];
    }];

    [ref setValue:@{
                    @"a": @{@".value": @1, @".priority": @1},
                    @"b": @{@".value": @2, @".priority": @2},
                    @"c": @{@".value": @3, @".priority": @3}
                    }];

    __block BOOL ready = NO;
    [[ref child:@"b"] setValue:[NSNull null] withCompletionBlock:^(NSError *error, FIRDatabaseReference *ref) {
        ready = YES;
    }];

    WAIT_FOR(ready);

    NSArray* expected = @[@{@"b": @2, @"c": @3}, @{@"a": @1, @"c": @3}];
    XCTAssertEqualObjects(snaps, expected, @"Incorrect snapshots.");
}

- (void)testChildChangedCausesChildRemovedEvent
{
    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];
    [[ref child:@"l/a"] setValue:@"1" andPriority:@"a"];
    [[ref child:@"l/b"] setValue:@"2" andPriority:@"b"];
    FIRDatabaseQuery *query = [[[[ref child:@"l"] queryOrderedByPriority] queryStartingAtValue:@"b"] queryEndingAtValue:@"d"];
    __block BOOL removed = NO;
    [query observeEventType:FIRDataEventTypeChildRemoved withBlock:^(FIRDataSnapshot *snapshot) {
        XCTAssertEqualObjects(snapshot.value, @"2", @"Incorrect snapshot");
        removed = YES;
    }];

    [[ref child:@"l/b"] setValue:@"4" andPriority:@"a"];

    WAIT_FOR(removed);
}

- (void) testQueryHasRef {
    FIRDatabaseReference *ref = [FTestHelpers getRandomNode];
    FIRDatabaseQuery *query = [ref queryOrderedByKey];
    XCTAssertEqualObjects([query.ref path], [ref path], @"Should have same path");
}

- (void) testQuerySnapshotChildrenRespectDefaultOrdering {
    FTupleFirebase* pair = [FTestHelpers getRandomNodePair];
    FIRDatabaseReference * writer = pair.one;
    FIRDatabaseReference * reader = pair.two;
    __block BOOL done = NO;

    NSDictionary* list = @{
        @"a": @{
            @"thisvaluefirst": @{ @".value": @true, @".priority": @1 },
            @"name": @{ @".value": @"Michael", @".priority": @2 },
            @"thisvaluelast": @{ @".value": @true, @".priority": @3 },
        },
        @"b": @{
            @"thisvaluefirst": @{ @".value": @true },
            @"name": @{ @".value": @"Rob", @".priority": @2 },
            @"thisvaluelast": @{ @".value": @true, @".priority": @3 },
        },
        @"c": @{
            @"thisvaluefirst": @{ @".value": @true, @".priority": @1 },
            @"name": @{ @".value": @"Jonny", @".priority": @2 },
            @"thisvaluelast": @{ @".value": @true, @".priority": @"somestring" },
        }
    };

    [writer setValue:list withCompletionBlock:^(NSError *error, FIRDatabaseReference *ref) {
        done = YES;
    }];
    WAIT_FOR(done);

    done = NO;
    [[reader queryOrderedByChild:@"name"] observeSingleEventOfType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
        NSArray *expectedKeys = @[@"thisvaluefirst", @"name", @"thisvaluelast"];
        NSArray *expectedNames = @[@"Jonny", @"Michael", @"Rob"];

        // Validate that snap.child() resets order to default for child snaps
        NSMutableArray *orderedKeys = [[NSMutableArray alloc] init];
        for (FIRDataSnapshot *childSnap in [snapshot childSnapshotForPath:@"b"].children) {
            [orderedKeys addObject:childSnap.key];
        }
        XCTAssertEqualObjects(expectedKeys, orderedKeys, @"Should have matching ordered lists of keys");

        // Validate that snap.forEach() resets ordering to default for child snaps
        NSMutableArray *orderedNames = [[NSMutableArray alloc] init];
        for (FIRDataSnapshot *childSnap in snapshot.children) {
            [orderedNames addObject:[childSnap childSnapshotForPath:@"name"].value];
            [orderedKeys removeAllObjects];
            for (FIRDataSnapshot *grandchildSnap in childSnap.children) {
                [orderedKeys addObject:grandchildSnap.key];
            }
            XCTAssertEqualObjects(expectedKeys, orderedKeys, @"Should have matching ordered lists of keys");
        }
        XCTAssertEqualObjects(expectedNames, orderedNames, @"Should have matching ordered lists of names");

        done = YES;
    }];
    WAIT_FOR(done);
}

- (void) testAddingListensForTheSamePathDoesNotCheckFail {
    // This bug manifests itself if there's a hierarchy of query listener, default listener and one-time listener
    // underneath.
    // In Java implementation, during one-time listener registration, sync-tree traversal stopped as soon as it found
    // a complete server cache (this is the case for not indexed query view). The problem is that the same traversal was
    // looking for a ancestor default view, and the early exit prevented from finding the default listener above the
    // one-time listener. Event removal code path wasn't removing the listener because it stopped as soon as it
    // found the default view. This left the zombie one-time listener and check failed on the second attempt to
    // create a listener for the same path (asana#61028598952586).

    FIRDatabaseReference * ref = [FTestHelpers getRandomNode];

    __block BOOL done = NO;

    [[ref child:@"child"] setValue:@{@"name": @"John"}];
    [[[ref queryOrderedByChild:@"name"] queryEqualToValue:@"John"] observeEventType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
        done = YES;
    }];
    WAIT_FOR(done);

    done = NO;
    [[[ref child:@"child"] child:@"favoriteToy"] observeSingleEventOfType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
        done = YES;
    }];
    WAIT_FOR(done);

    done = NO;
    [[[ref child:@"child"] child:@"favoriteToy"] observeSingleEventOfType:FIRDataEventTypeValue withBlock:^(FIRDataSnapshot *snapshot) {
        done = YES;
    }];
    WAIT_FOR(done);
}

@end