firebase-ios-sdk/FirebaseDatabase/Tests/Unit/FIRDataSnapshotTests.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 "FirebaseDatabase/Tests/Unit/FIRDataSnapshotTests.h"
#import "FirebaseDatabase/Sources/Api/Private/FIRDataSnapshot_Private.h"
#import "FirebaseDatabase/Sources/FIRDatabaseConfig_Private.h"
#import "FirebaseDatabase/Sources/FPathIndex.h"
#import "FirebaseDatabase/Sources/FValueIndex.h"
#import "FirebaseDatabase/Sources/Public/FirebaseDatabase/FIRDatabaseReference.h"
#import "FirebaseDatabase/Sources/Snapshot/FChildrenNode.h"
#import "FirebaseDatabase/Sources/Snapshot/FEmptyNode.h"
#import "FirebaseDatabase/Sources/Snapshot/FLeafNode.h"
#import "FirebaseDatabase/Sources/Snapshot/FSnapshotUtilities.h"
#import "FirebaseDatabase/Sources/Utilities/FUtilities.h"
#import "FirebaseDatabase/Sources/third_party/FImmutableSortedDictionary/FImmutableSortedDictionary/FImmutableSortedDictionary.h"
#import "FirebaseDatabase/Tests/Helpers/FTestHelpers.h"

@implementation FIRDataSnapshotTests

- (void)setUp {
  [super setUp];

  // Set-up code here.
}

- (void)tearDown {
  // Tear-down code here.

  [super tearDown];
}

- (FIRDataSnapshot*)snapshotFor:(id)jsonDict {
  FIRDatabaseConfig* config = [FTestHelpers defaultConfig];
  FRepoInfo* repoInfo = [[FRepoInfo alloc] initWithHost:@"example.com"
                                               isSecure:NO
                                          withNamespace:@"default"];
  FIRDatabaseReference* dummyRef =
      [[FIRDatabaseReference alloc] initWithRepo:[FRepoManager getRepo:repoInfo config:config]
                                            path:[FPath empty]];
  FIndexedNode* indexed = [FIndexedNode indexedNodeWithNode:[FSnapshotUtilities nodeFrom:jsonDict]];
  FIRDataSnapshot* snapshot = [[FIRDataSnapshot alloc] initWithRef:dummyRef indexedNode:indexed];
  return snapshot;
}

- (void)testCreationLeafNodesVariousTypes {
  id<FNode> fortyTwo = [FSnapshotUtilities nodeFrom:@42];
  FLeafNode* x = [[FLeafNode alloc] initWithValue:@5 withPriority:fortyTwo];

  XCTAssertEqualObjects(x.val, @5, @"Values are the same");
  XCTAssertEqualObjects(x.getPriority, [FSnapshotUtilities nodeFrom:@42], @"Priority is the same");
  XCTAssertTrue([x isLeafNode], @"Node is a leaf");

  x = [[FLeafNode alloc] initWithValue:@"test"];
  XCTAssertEqualObjects(x.value, @"test", @"Check if leaf node is holding onto a string value");

  x = [[FLeafNode alloc] initWithValue:[NSNumber numberWithBool:YES]];
  XCTAssertTrue([x.value boolValue], @"Check if leaf node is holding onto a YES boolean");

  x = [[FLeafNode alloc] initWithValue:[NSNumber numberWithBool:NO]];
  XCTAssertFalse([x.value boolValue], @"Check if leaf node is holding onto a NO boolean");
}

- (void)testUpdatingPriorityWithoutChangingOld {
  FLeafNode* x =
      [[FLeafNode alloc] initWithValue:@"test"
                          withPriority:[FSnapshotUtilities nodeFrom:[NSNumber numberWithInt:42]]];
  FLeafNode* y = [x updatePriority:[FSnapshotUtilities nodeFrom:[NSNumber numberWithInt:187]]];

  // old node is the same
  XCTAssertEqualObjects(x.value, @"test", @"Values of old node are the same");
  XCTAssertEqualObjects(x.getPriority, [FSnapshotUtilities nodeFrom:[NSNumber numberWithInt:42]],
                        @"Priority of old node is the same.");

  // new node has the new priority but the old value
  XCTAssertEqualObjects(y.value, @"test", @"Values of old node are the same");
  XCTAssertEqualObjects(y.getPriority, [FSnapshotUtilities nodeFrom:[NSNumber numberWithInt:187]],
                        @"Priority of new node is update");
}

- (void)testUpdateImmediateChildReturnsANewChildrenNode {
  FLeafNode* x =
      [[FLeafNode alloc] initWithValue:@"test"
                          withPriority:[FSnapshotUtilities nodeFrom:[NSNumber numberWithInt:42]]];
  FChildrenNode* y = [x updateImmediateChild:@"test"
                                withNewChild:[[FLeafNode alloc] initWithValue:@"foo"]];

  XCTAssertFalse([y isLeafNode], @"New node is no longer a leaf");
  XCTAssertEqualObjects(y.getPriority, [FSnapshotUtilities nodeFrom:[NSNumber numberWithInt:42]],
                        @"Priority of new node is update");

  XCTAssertEqualObjects([[y getImmediateChild:@"test"] val], @"foo",
                        @"Child node has the correct value");
}

- (void)testGetImmediateChildOnLeafNode {
  FLeafNode* x = [[FLeafNode alloc] initWithValue:@"test"];
  XCTAssertEqualObjects([x getImmediateChild:@"foo"], [FEmptyNode emptyNode],
                        @"Get immediate child on leaf node returns empty node");
}

- (void)testGetChildReturnsEmptyNode {
  FLeafNode* x = [[FLeafNode alloc] initWithValue:@"test"];
  XCTAssertEqualObjects([x getChild:[[FPath alloc] initWith:@"foo/bar"]], [FEmptyNode emptyNode],
                        @"Get child returns an empty node.");
}

- (NSComparator)defaultComparator {
  return ^(id obj1, id obj2) {
    if ([obj1 respondsToSelector:@selector(compare:)] &&
        [obj2 respondsToSelector:@selector(compare:)]) {
      return [obj1 compare:obj2];
    } else {
      if (obj1 < obj2) {
        return (NSComparisonResult)NSOrderedAscending;
      } else if (obj1 > obj2) {
        return (NSComparisonResult)NSOrderedDescending;
      } else {
        return (NSComparisonResult)NSOrderedSame;
      }
    }
  };
}

- (void)testUpdateImmediateChildWithNewNode {
  FImmutableSortedDictionary* children =
      [FImmutableSortedDictionary dictionaryWithComparator:[self defaultComparator]];
  FChildrenNode* x = [[FChildrenNode alloc] initWithChildren:children];
  FLeafNode* newValue = [[FLeafNode alloc] initWithValue:@"new value"];
  FChildrenNode* y = [x updateImmediateChild:@"test" withNewChild:newValue];

  XCTAssertEqualObjects(x.children, children, @"Original object stays the same");
  XCTAssertEqualObjects([y.children objectForKey:@"test"], newValue,
                        @"New internal node with the proper new value");
  XCTAssertEqualObjects([[y.children objectForKey:@"test"] val], @"new value",
                        @"Check the payload");
}

- (void)testUpdatechildWithNewNode {
  FImmutableSortedDictionary* children =
      [FImmutableSortedDictionary dictionaryWithComparator:[self defaultComparator]];
  FChildrenNode* x = [[FChildrenNode alloc] initWithChildren:children];
  FLeafNode* newValue = [[FLeafNode alloc] initWithValue:@"new value"];
  FChildrenNode* y = [x updateChild:[[FPath alloc] initWith:@"test/foo"] withNewChild:newValue];
  XCTAssertEqualObjects(x.children, children, @"Original object stays the same");
  XCTAssertEqualObjects([y getChild:[[FPath alloc] initWith:@"test/foo"]], newValue,
                        @"Check if the updateChild held");
  XCTAssertEqualObjects([[y getChild:[[FPath alloc] initWith:@"test/foo"]] val], @"new value",
                        @"Check the payload");
}

- (void)testObjectTypes {
  XCTAssertEqualObjects(@"string", [FUtilities getJavascriptType:@""], @"Check string type");
  XCTAssertEqualObjects(@"string", [FUtilities getJavascriptType:@"moo"], @"Check string type");

  XCTAssertEqualObjects(@"boolean", [FUtilities getJavascriptType:@YES], @"Check boolean type");
  XCTAssertEqualObjects(@"boolean", [FUtilities getJavascriptType:@NO], @"Check boolean type");

  XCTAssertEqualObjects(@"number", [FUtilities getJavascriptType:@5], @"Check number type");
  XCTAssertEqualObjects(@"number", [FUtilities getJavascriptType:@5.5], @"Check number type");
  XCTAssertEqualObjects(@"number", [FUtilities getJavascriptType:@0], @"Check number type");
  XCTAssertEqualObjects(@"number", [FUtilities getJavascriptType:@8273482734],
                        @"Check number type");
  XCTAssertEqualObjects(@"number", [FUtilities getJavascriptType:@-2], @"Check number type");
  XCTAssertEqualObjects(@"number", [FUtilities getJavascriptType:@-2.11], @"Check number type");
}

- (void)testNodeHashWorksCorrectly {
  id<FNode> node = [FSnapshotUtilities nodeFrom:@{
    @"intNode" : @4,
    @"doubleNode" : @4.5623,
    @"stringNode" : @"hey guys",
    @"boolNode" : @YES
  }];

  XCTAssertEqualObjects(@"eVih19a6ZDz3NL32uVBtg9KSgQY=",
                        [[node getImmediateChild:@"intNode"] dataHash], @"Check integer node");
  XCTAssertEqualObjects(@"vf1CL0tIRwXXunHcG/irRECk3lY=",
                        [[node getImmediateChild:@"doubleNode"] dataHash], @"Check double node");
  XCTAssertEqualObjects(@"CUNLXWpCVoJE6z7z1vE57lGaKAU=",
                        [[node getImmediateChild:@"stringNode"] dataHash], @"Check string node");
  XCTAssertEqualObjects(@"E5z61QM0lN/U2WsOnusszCTkR8M=",
                        [[node getImmediateChild:@"boolNode"] dataHash], @"Check boolean node");
  XCTAssertEqualObjects(@"6Mc4jFmNdrLVIlJJjz2/MakTK9I=", [node dataHash], @"Check compound node");
}

- (void)testNodeHashWorksCorrectlyWithPriorities {
  id<FNode> node = [FSnapshotUtilities nodeFrom:@{
    @"root" : @{@"c" : @{@".value" : @99, @".priority" : @"abc"}, @".priority" : @"def"}
  }];

  XCTAssertEqualObjects(@"Fm6tzN4CVEu5WxFDZUdTtqbTVaA=", [node dataHash], @"Check compound node");
}

- (void)testGetPredecessorChild {
  id<FNode> node = [FSnapshotUtilities
      nodeFrom:@{@"d" : @YES, @"a" : @YES, @"g" : @YES, @"c" : @YES, @"e" : @YES}];

  XCTAssertNil([node predecessorChildKey:@"a"], @"Check the first one sorted properly");
  XCTAssertEqualObjects([node predecessorChildKey:@"c"], @"a", @"Check a comes before c");
  XCTAssertEqualObjects([node predecessorChildKey:@"d"], @"c", @"Check c comes before d");
  XCTAssertEqualObjects([node predecessorChildKey:@"e"], @"d", @"Check d comes before e");
  XCTAssertEqualObjects([node predecessorChildKey:@"g"], @"e", @"Check e comes before g");
}

- (void)testSortedChildrenGetPredecessorChildWorksCorrectly {
  // XXX impl SortedChildren
}

- (void)testSortedChildrenUpdateImmediateChildrenWorksCorrectly {
  // XXX imple SortedChildren
}

- (void)testDataSnapshotHasChildrenWorks {
  FIRDataSnapshot* snap = [self snapshotFor:@{}];
  XCTAssertFalse([snap hasChildren], @"Empty dict has no children");

  snap = [self snapshotFor:@5];
  XCTAssertFalse([snap hasChildren], @"Leaf node has no children");

  snap = [self snapshotFor:@{@"x" : @5}];
  XCTAssertTrue([snap hasChildren], @"Properly has children");
}

- (void)testDataSnapshotValWorks {
  FIRDataSnapshot* snap = [self snapshotFor:@5];
  XCTAssertEqualObjects([snap value], @5, @"Leaf node values are correct");

  snap = [self snapshotFor:@{}];
  XCTAssertTrue([snap value] == [NSNull null], @"Snapshot value is properly null");

  NSDictionary* dict = @{@"x" : @5, @"y" : @{@"ya" : @1, @"yb" : @2, @"yc" : @{@"yca" : @3}}};

  snap = [self snapshotFor:dict];
  XCTAssertTrue([dict isEqualToDictionary:[snap value]], @"Check if the dictionaries are the same");
}

- (void)testDataSnapshotChildWorks {
  FIRDataSnapshot* snap = [self snapshotFor:@{@"x" : @5, @"y" : @{@"yy" : @3, @"yz" : @4}}];

  XCTAssertEqualObjects([[snap childSnapshotForPath:@"x"] value], @5, @"Check x");
  NSDictionary* dict = @{@"yy" : @3, @"yz" : @4};
  XCTAssertTrue([[[snap childSnapshotForPath:@"y"] value] isEqualToDictionary:dict], @"Check y");

  XCTAssertEqualObjects([[[snap childSnapshotForPath:@"y"] childSnapshotForPath:@"yy"] value], @3,
                        @"Check y/yy");
  XCTAssertEqualObjects([[snap childSnapshotForPath:@"y/yz"] value], @4, @"Check y/yz");
  XCTAssertTrue([[snap childSnapshotForPath:@"z"] value] == [NSNull null], @"Check nonexistent z");
  XCTAssertTrue([[snap childSnapshotForPath:@"x/y"] value] == [NSNull null],
                @"Check value of existent internal node");
  XCTAssertTrue(
      [[[snap childSnapshotForPath:@"x"] childSnapshotForPath:@"y"] value] == [NSNull null],
      @"Check value of existent internal node");
}

- (void)testDataSnapshotHasChildWorks {
  FIRDataSnapshot* snap = [self snapshotFor:@{@"x" : @5, @"y" : @{@"yy" : @3, @"yz" : @4}}];

  XCTAssertTrue([snap hasChild:@"x"], @"Has child");
  XCTAssertTrue([snap hasChild:@"y/yy"], @"Has child");

  XCTAssertFalse([snap hasChild:@"dinosaur dinosaucer"], @"No child");
  XCTAssertFalse([[snap childSnapshotForPath:@"x"] hasChild:@"anything"], @"No child");
  XCTAssertFalse([snap hasChild:@"x/anything/at/all"], @"No child");
}

- (void)testDataSnapshotNameWorks {
  FIRDataSnapshot* snap = [self snapshotFor:@{@"a" : @{@"b" : @{@"c" : @5}}}];

  XCTAssertEqualObjects([[snap childSnapshotForPath:@"a"] key], @"a", @"Check child key");
  XCTAssertEqualObjects([[snap childSnapshotForPath:@"a/b/c"] key], @"c", @"Check child key");
  XCTAssertEqualObjects([[snap childSnapshotForPath:@"/a/b/c"] key], @"c", @"Check child key");
  XCTAssertEqualObjects([[snap childSnapshotForPath:@"/a/b/c/"] key], @"c", @"Check child key");
  XCTAssertEqualObjects([[snap childSnapshotForPath:@"////a///b////c///"] key], @"c",
                        @"Check child key");
  XCTAssertEqualObjects([[snap childSnapshotForPath:@"////"] key], [snap key], @"Check root key");

  XCTAssertEqualObjects([[snap childSnapshotForPath:@"/z/q/r/v////m"] key], @"m",
                        @"Should also work for nonexistent paths");
}

- (void)testDataSnapshotForEachWithNoPriorities {
  FIRDataSnapshot* snap = [self snapshotFor:@{
    @"a" : @1,
    @"z" : @26,
    @"m" : @13,
    @"n" : @14,
    @"c" : @3,
    @"b" : @2,
    @"e" : @5
  }];

  NSMutableString* out = [[NSMutableString alloc] init];
  for (FIRDataSnapshot* child in snap.children) {
    [out appendFormat:@"%@:%@:", [child key], [child value]];
  }

  XCTAssertTrue([out isEqualToString:@"a:1:b:2:c:3:e:5:m:13:n:14:z:26:"], @"Proper order");
}

- (void)testDataSnapshotForEachWorksWithNumericPriorities {
  FIRDataSnapshot* snap = [self snapshotFor:@{
    @"a" : @{@".value" : @1, @".priority" : @26},
    @"z" : @{@".value" : @26, @".priority" : @1},
    @"m" : @{@".value" : @13, @".priority" : @14},
    @"n" : @{@".value" : @14, @".priority" : @12},
    @"c" : @{@".value" : @3, @".priority" : @24},
    @"b" : @{@".value" : @2, @".priority" : @25},
    @"e" : @{@".value" : @5, @".priority" : @22},
  }];

  NSMutableString* out = [[NSMutableString alloc] init];
  for (FIRDataSnapshot* child in snap.children) {
    [out appendFormat:@"%@:%@:", [child key], [child value]];
  }

  XCTAssertTrue([out isEqualToString:@"z:26:n:14:m:13:e:5:c:3:b:2:a:1:"], @"Proper order");
}

- (void)testDataSnapshotForEachWorksWithNumericPrioritiesAsStrings {
  FIRDataSnapshot* snap = [self snapshotFor:@{
    @"a" : @{@".value" : @1, @".priority" : @"26"},
    @"z" : @{@".value" : @26, @".priority" : @"1"},
    @"m" : @{@".value" : @13, @".priority" : @"14"},
    @"n" : @{@".value" : @14, @".priority" : @"12"},
    @"c" : @{@".value" : @3, @".priority" : @"24"},
    @"b" : @{@".value" : @2, @".priority" : @"25"},
    @"e" : @{@".value" : @5, @".priority" : @"22"},
  }];

  NSMutableString* out = [[NSMutableString alloc] init];
  for (FIRDataSnapshot* child in snap.children) {
    [out appendFormat:@"%@:%@:", [child key], [child value]];
  }

  XCTAssertTrue([out isEqualToString:@"z:26:n:14:m:13:e:5:c:3:b:2:a:1:"], @"Proper order");
}

- (void)testDataSnapshotForEachWorksAlphaPriorities {
  FIRDataSnapshot* snap = [self snapshotFor:@{
    @"a" : @{@".value" : @1, @".priority" : @"first"},
    @"z" : @{@".value" : @26, @".priority" : @"second"},
    @"m" : @{@".value" : @13, @".priority" : @"third"},
    @"n" : @{@".value" : @14, @".priority" : @"fourth"},
    @"c" : @{@".value" : @3, @".priority" : @"fifth"},
    @"b" : @{@".value" : @2, @".priority" : @"sixth"},
    @"e" : @{@".value" : @5, @".priority" : @"seventh"},
  }];

  NSMutableString* output = [[NSMutableString alloc] init];
  NSMutableArray* priorities = [[NSMutableArray alloc] init];
  for (FIRDataSnapshot* child in snap.children) {
    [output appendFormat:@"%@:%@:", child.key, child.value];
    [priorities addObject:child.priority];
  }

  XCTAssertTrue([output isEqualToString:@"c:3:a:1:n:14:z:26:e:5:b:2:m:13:"], @"Proper order");
  NSArray* expected = @[ @"fifth", @"first", @"fourth", @"second", @"seventh", @"sixth", @"third" ];
  XCTAssertTrue([priorities isEqualToArray:expected], @"Correct priorities");
  XCTAssertTrue(snap.childrenCount == 7, @"Got correct children count");
}

- (void)testDataSnapshotForEachWorksWithMixedPriorities {
  FIRDataSnapshot* snap = [self snapshotFor:@{
    @"alpha42" : @{@".value" : @1, @".priority" : @"zed"},
    @"noPriorityC" : @{@".value" : @1, @".priority" : [NSNull null]},
    @"alpha14" : @{@".value" : @1, @".priority" : @"500"},
    @"noPriorityB" : @{@".value" : @1, @".priority" : [NSNull null]},
    @"num80" : @{@".value" : @1, @".priority" : @4000.1},
    @"alpha13" : @{@".value" : @1, @".priority" : @"4000"},
    @"alpha11" : @{@".value" : @1, @".priority" : @"24"},
    @"alpha41" : @{@".value" : @1, @".priority" : @"zed"},
    @"alpha20" : @{@".value" : @1, @".priority" : @"horse"},
    @"num20" : @{@".value" : @1, @".priority" : @123},
    @"num70" : @{@".value" : @1, @".priority" : @4000.01},
    @"noPriorityA" : @{@".value" : @1, @".priority" : [NSNull null]},
    @"alpha30" : @{@".value" : @1, @".priority" : @"tree"},
    @"alpha12" : @{@".value" : @1, @".priority" : @"300"},
    @"num60" : @{@".value" : @1, @".priority" : @4000.001},
    @"alpha10" : @{@".value" : @1, @".priority" : @"0horse"},
    @"num42" : @{@".value" : @1, @".priority" : @500},
    @"alpha40" : @{@".value" : @1, @".priority" : @"zed"},
    @"num40" : @{@".value" : @1, @".priority" : @500}
  }];

  NSMutableString* out = [[NSMutableString alloc] init];
  for (FIRDataSnapshot* child in snap.children) {
    [out appendFormat:@"%@, ", [child key]];
  }

  NSString* expected =
      @"noPriorityA, noPriorityB, noPriorityC, num20, num40, num42, num60, num70, num80, alpha10, "
      @"alpha11, alpha12, alpha13, alpha14, alpha20, alpha30, alpha40, alpha41, alpha42, ";

  XCTAssertTrue([expected isEqualToString:out], @"Proper ordering seen");
}

- (void)testIgnoresNullValues {
  FIRDataSnapshot* snap = [self snapshotFor:@{@"a" : @1, @"b" : [NSNull null]}];
  XCTAssertFalse([snap hasChild:@"b"], @"Should not have b, it was null");
}

- (void)testNameComparator {
  NSComparator keyComparator = [FUtilities keyComparator];
  XCTAssertEqual(keyComparator(@"1234", @"1234"), NSOrderedSame, @"NameComparator compares ints");
  XCTAssertEqual(keyComparator(@"1234", @"12345"), NSOrderedAscending,
                 @"NameComparator compares ints");
  XCTAssertEqual(keyComparator(@"4321", @"1234"), NSOrderedDescending,
                 @"NameComparator compares ints");
  XCTAssertEqual(keyComparator(@"1234", @"zzzz"), NSOrderedAscending,
                 @"NameComparator priorities ints");
  XCTAssertEqual(keyComparator(@"4321", @"12a"), NSOrderedAscending,
                 @"NameComparator priorities ints");
  XCTAssertEqual(keyComparator(@"abc", @"abcd"), NSOrderedAscending,
                 @"NameComparator uses lexiographical sorting for strings.");
  XCTAssertEqual(keyComparator(@"zzzz", @"aaaa"), NSOrderedDescending,
                 @"NameComparator compares strings");
  XCTAssertEqual(keyComparator(@"-1234", @"0"), NSOrderedAscending,
                 @"NameComparator compares negative values");
  XCTAssertEqual(keyComparator(@"-1234", @"-1234"), NSOrderedSame,
                 @"NameComparator compares negative values");
  XCTAssertEqual(keyComparator(@"-1234", @"-4321"), NSOrderedDescending,
                 @"NameComparator compares negative values");
  XCTAssertEqual(keyComparator(@"-1234", @"-"), NSOrderedAscending,
                 @"NameComparator does not parse - as integer");
  XCTAssertEqual(keyComparator(@"-", @"1234"), NSOrderedDescending,
                 @"NameComparator does not parse - as integer");
}

- (void)testExistsWorks {
  FIRDataSnapshot* snap;

  snap = [self snapshotFor:@{}];
  XCTAssertFalse([snap exists], @"Should not exist");

  snap = [self snapshotFor:@{@".priority" : @"1"}];
  XCTAssertFalse([snap exists], @"Should not exist");

  snap = [self snapshotFor:[NSNull null]];
  XCTAssertFalse([snap exists], @"Should not exist");

  snap = [self snapshotFor:[NSNumber numberWithBool:YES]];
  XCTAssertTrue([snap exists], @"Should exist");

  snap = [self snapshotFor:@5];
  XCTAssertTrue([snap exists], @"Should exist");

  snap = [self snapshotFor:@{@"x" : @5}];
  XCTAssertTrue([snap exists], @"Should exist");
}

- (void)testUpdatingEmptyChildDoesntOverwriteLeafNode {
  FLeafNode* node = [[FLeafNode alloc] initWithValue:@"value"];
  XCTAssertEqualObjects(node,
                        [node updateChild:[[FPath alloc] initWith:@".priority"]
                             withNewChild:[FEmptyNode emptyNode]],
                        @"Update should not affect node.");
  XCTAssertEqualObjects(node,
                        [node updateChild:[[FPath alloc] initWith:@"child"]
                             withNewChild:[FEmptyNode emptyNode]],
                        @"Update should not affect node.");
  XCTAssertEqualObjects(node,
                        [node updateChild:[[FPath alloc] initWith:@"child/.priority"]
                             withNewChild:[FEmptyNode emptyNode]],
                        @"Update should not affect node.");
  XCTAssertEqualObjects(node,
                        [node updateImmediateChild:@"child" withNewChild:[FEmptyNode emptyNode]],
                        @"Update should not affect node.");
  XCTAssertEqualObjects(
      node, [node updateImmediateChild:@".priority" withNewChild:[FEmptyNode emptyNode]],
      @"Update should not affect node.");
}

/* This was reported by a customer, which broke because 유주연 > 윤규완오빠 but also 윤규완오빠 >
 * 유주연  with the default string comparison... */
- (void)testUnicodeEquality {
  FNamedNode* node1 = [[FNamedNode alloc] initWithName:@"a"
                                               andNode:[[FLeafNode alloc] initWithValue:@"유주연"]];
  FNamedNode* node2 =
      [[FNamedNode alloc] initWithName:@"a"
                               andNode:[[FLeafNode alloc] initWithValue:@"윤규완오빠"]];
  id<FIndex> index = [FValueIndex valueIndex];

  // x < y should imply y > x
  XCTAssertEqual([index compareNamedNode:node1 toNamedNode:node2], -[index compareNamedNode:node2
                                                                                toNamedNode:node1]);
}

@end