Port FSTDocumentKeySet to C++ DocumentKeySet (#1229)

* Define a Comparator for DocumentKey

* Automated migration from FSTDocumentKeySet to DocumentKeySet

* Manual fixups for DocumentKeySet

* Delete FSTDocumentKeySet

2 files changed, 44 insertions, 41 deletions

diff --git a/Firestore/Example/Tests/Core/FSTQueryListenerTests.mm b/Firestore/Example/Tests/Core/FSTQueryListenerTests.mm
index 0454152..7ae9704 100644
--- a/Firestore/Example/Tests/Core/FSTQueryListenerTests.mm
+++ b/Firestore/Example/Tests/Core/FSTQueryListenerTests.mm
@@ -27,6 +27,8 @@
 
 #import "Firestore/Example/Tests/Util/FSTHelpers.h"
 
+using firebase::firestore::model::DocumentKeySet;
+
 NS_ASSUME_NONNULL_BEGIN
 
 @interface FSTQueryListenerTests : XCTestCase
@@ -53,7 +55,7 @@ NS_ASSUME_NONNULL_BEGIN
   FSTQueryListener *listener = [self listenToQuery:query accumulatingSnapshots:accum];
   FSTQueryListener *otherListener = [self listenToQuery:query accumulatingSnapshots:otherAccum];
 
-  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:[FSTDocumentKeySet keySet]];
+  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:DocumentKeySet{}];
   FSTViewSnapshot *snap1 = FSTTestApplyChanges(view, @[ doc1, doc2 ], nil);
   FSTViewSnapshot *snap2 = FSTTestApplyChanges(view, @[ doc2prime ], nil);
 
@@ -107,7 +109,7 @@ NS_ASSUME_NONNULL_BEGIN
 
   FSTQueryListener *listener = [self listenToQuery:query accumulatingSnapshots:accum];
 
-  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:[FSTDocumentKeySet keySet]];
+  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:DocumentKeySet{}];
   FSTViewSnapshot *snap1 = FSTTestApplyChanges(view, @[], nil);
 
   FSTTargetChange *ackTarget =
@@ -136,7 +138,7 @@ NS_ASSUME_NONNULL_BEGIN
               [listener mute];
             }];
 
-  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:[FSTDocumentKeySet keySet]];
+  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:DocumentKeySet{}];
   FSTViewSnapshot *viewSnapshot1 = FSTTestApplyChanges(view, @[ doc1 ], nil);
   FSTViewSnapshot *viewSnapshot2 = FSTTestApplyChanges(view, @[ doc2 ], nil);
 
@@ -178,7 +180,7 @@ NS_ASSUME_NONNULL_BEGIN
   FSTQueryListener *fullListener =
       [self listenToQuery:query options:options accumulatingSnapshots:fullAccum];
 
-  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:[FSTDocumentKeySet keySet]];
+  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:DocumentKeySet{}];
   FSTViewSnapshot *snap1 = FSTTestApplyChanges(view, @[ doc1 ], nil);
 
   FSTTargetChange *ackTarget =
@@ -218,7 +220,7 @@ NS_ASSUME_NONNULL_BEGIN
   FSTQueryListener *fullListener =
       [self listenToQuery:query options:options accumulatingSnapshots:fullAccum];
 
-  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:[FSTDocumentKeySet keySet]];
+  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:DocumentKeySet{}];
   FSTViewSnapshot *snap1 = FSTTestApplyChanges(view, @[ doc1, doc2 ], nil);
   FSTViewSnapshot *snap2 = FSTTestApplyChanges(view, @[ doc1Prime ], nil);
   FSTViewSnapshot *snap3 = FSTTestApplyChanges(view, @[ doc3 ], nil);
@@ -265,7 +267,7 @@ NS_ASSUME_NONNULL_BEGIN
   FSTQueryListener *fullListener =
       [self listenToQuery:query options:options accumulatingSnapshots:fullAccum];
 
-  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:[FSTDocumentKeySet keySet]];
+  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:DocumentKeySet{}];
   FSTViewSnapshot *snap1 = FSTTestApplyChanges(view, @[ doc1, doc2 ], nil);
   FSTViewSnapshot *snap2 = FSTTestApplyChanges(view, @[ doc1Prime ], nil);
   FSTViewSnapshot *snap3 = FSTTestApplyChanges(view, @[ doc3 ], nil);
@@ -298,7 +300,7 @@ NS_ASSUME_NONNULL_BEGIN
   FSTQueryListener *filteredListener =
       [self listenToQuery:query accumulatingSnapshots:filteredAccum];
 
-  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:[FSTDocumentKeySet keySet]];
+  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:DocumentKeySet{}];
   FSTViewSnapshot *snap1 = FSTTestApplyChanges(view, @[ doc1, doc2 ], nil);
   FSTViewSnapshot *snap2 = FSTTestApplyChanges(view, @[ doc1Prime, doc3 ], nil);
 
@@ -331,7 +333,7 @@ NS_ASSUME_NONNULL_BEGIN
                                                                         waitForSyncWhenOnline:YES]
           accumulatingSnapshots:events];
 
-  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:[FSTDocumentKeySet keySet]];
+  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:DocumentKeySet{}];
   FSTViewSnapshot *snap1 = FSTTestApplyChanges(view, @[ doc1 ], nil);
   FSTViewSnapshot *snap2 = FSTTestApplyChanges(view, @[ doc2 ], nil);
   FSTViewSnapshot *snap3 =
@@ -374,7 +376,7 @@ NS_ASSUME_NONNULL_BEGIN
                                                                         waitForSyncWhenOnline:YES]
           accumulatingSnapshots:events];
 
-  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:[FSTDocumentKeySet keySet]];
+  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:DocumentKeySet{}];
   FSTViewSnapshot *snap1 = FSTTestApplyChanges(view, @[ doc1 ], nil);
   FSTViewSnapshot *snap2 = FSTTestApplyChanges(view, @[ doc2 ], nil);
 
@@ -415,7 +417,7 @@ NS_ASSUME_NONNULL_BEGIN
                                            options:[FSTListenOptions defaultOptions]
                              accumulatingSnapshots:events];
 
-  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:[FSTDocumentKeySet keySet]];
+  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:DocumentKeySet{}];
   FSTViewSnapshot *snap1 = FSTTestApplyChanges(view, @[], nil);
 
   [listener applyChangedOnlineState:FSTOnlineStateOnline];   // no event
@@ -441,7 +443,7 @@ NS_ASSUME_NONNULL_BEGIN
                                            options:[FSTListenOptions defaultOptions]
                              accumulatingSnapshots:events];
 
-  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:[FSTDocumentKeySet keySet]];
+  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:DocumentKeySet{}];
   FSTViewSnapshot *snap1 = FSTTestApplyChanges(view, @[], nil);
 
   [listener applyChangedOnlineState:FSTOnlineStateOffline];  // no event
diff --git a/Firestore/Example/Tests/Core/FSTViewTests.mm b/Firestore/Example/Tests/Core/FSTViewTests.mm
index 63ce711..ec62d82 100644
--- a/Firestore/Example/Tests/Core/FSTViewTests.mm
+++ b/Firestore/Example/Tests/Core/FSTViewTests.mm
@@ -34,6 +34,7 @@
 
 namespace testutil = firebase::firestore::testutil;
 using firebase::firestore::model::ResourcePath;
+using firebase::firestore::model::DocumentKeySet;
 
 NS_ASSUME_NONNULL_BEGIN
 
@@ -49,7 +50,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 - (void)testAddsDocumentsBasedOnQuery {
   FSTQuery *query = [self queryForMessages];
-  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:[FSTDocumentKeySet keySet]];
+  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:DocumentKeySet{}];
 
   FSTDocument *doc1 = FSTTestDoc("rooms/eros/messages/1", 0, @{@"text" : @"msg1"}, NO);
   FSTDocument *doc2 = FSTTestDoc("rooms/eros/messages/2", 0, @{@"text" : @"msg2"}, NO);
@@ -77,7 +78,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 - (void)testRemovesDocuments {
   FSTQuery *query = [self queryForMessages];
-  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:[FSTDocumentKeySet keySet]];
+  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:DocumentKeySet{}];
 
   FSTDocument *doc1 = FSTTestDoc("rooms/eros/messages/1", 0, @{@"text" : @"msg1"}, NO);
   FSTDocument *doc2 = FSTTestDoc("rooms/eros/messages/2", 0, @{@"text" : @"msg2"}, NO);
@@ -108,7 +109,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 - (void)testReturnsNilIfThereAreNoChanges {
   FSTQuery *query = [self queryForMessages];
-  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:[FSTDocumentKeySet keySet]];
+  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:DocumentKeySet{}];
 
   FSTDocument *doc1 = FSTTestDoc("rooms/eros/messages/1", 0, @{@"text" : @"msg1"}, NO);
   FSTDocument *doc2 = FSTTestDoc("rooms/eros/messages/2", 0, @{@"text" : @"msg2"}, NO);
@@ -123,7 +124,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 - (void)testDoesNotReturnNilForFirstChanges {
   FSTQuery *query = [self queryForMessages];
-  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:[FSTDocumentKeySet keySet]];
+  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:DocumentKeySet{}];
 
   FSTViewSnapshot *snapshot = FSTTestApplyChanges(view, @[], nil);
   XCTAssertNotNil(snapshot);
@@ -137,7 +138,7 @@ NS_ASSUME_NONNULL_BEGIN
                                    value:[FSTDoubleValue doubleValue:2]];
   query = [query queryByAddingFilter:filter];
 
-  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:[FSTDocumentKeySet keySet]];
+  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:DocumentKeySet{}];
   FSTDocument *doc1 = FSTTestDoc("rooms/eros/messages/1", 0, @{ @"sort" : @1 }, NO);
   FSTDocument *doc2 = FSTTestDoc("rooms/eros/messages/2", 0, @{ @"sort" : @2 }, NO);
   FSTDocument *doc3 = FSTTestDoc("rooms/eros/messages/3", 0, @{ @"sort" : @3 }, NO);
@@ -169,7 +170,7 @@ NS_ASSUME_NONNULL_BEGIN
                                    value:[FSTDoubleValue doubleValue:2]];
   query = [query queryByAddingFilter:filter];
 
-  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:[FSTDocumentKeySet keySet]];
+  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:DocumentKeySet{}];
   FSTDocument *doc1 = FSTTestDoc("rooms/eros/messages/1", 0, @{ @"sort" : @1 }, NO);
   FSTDocument *doc2 = FSTTestDoc("rooms/eros/messages/2", 0, @{ @"sort" : @3 }, NO);
   FSTDocument *doc3 = FSTTestDoc("rooms/eros/messages/3", 0, @{ @"sort" : @2 }, NO);
@@ -205,7 +206,7 @@ NS_ASSUME_NONNULL_BEGIN
 - (void)testRemovesDocumentsForQueryWithLimit {
   FSTQuery *query = [self queryForMessages];
   query = [query queryBySettingLimit:2];
-  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:[FSTDocumentKeySet keySet]];
+  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:DocumentKeySet{}];
 
   FSTDocument *doc1 = FSTTestDoc("rooms/eros/messages/1", 0, @{@"text" : @"msg1"}, NO);
   FSTDocument *doc2 = FSTTestDoc("rooms/eros/messages/2", 0, @{@"text" : @"msg2"}, NO);
@@ -239,7 +240,7 @@ NS_ASSUME_NONNULL_BEGIN
   query = [query queryByAddingSortOrder:[FSTSortOrder sortOrderWithFieldPath:testutil::Field("num")
                                                                    ascending:YES]];
   query = [query queryBySettingLimit:2];
-  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:[FSTDocumentKeySet keySet]];
+  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:DocumentKeySet{}];
 
   FSTDocument *doc1 = FSTTestDoc("rooms/eros/messages/1", 0, @{ @"num" : @1 }, NO);
   FSTDocument *doc2 = FSTTestDoc("rooms/eros/messages/2", 0, @{ @"num" : @2 }, NO);
@@ -283,7 +284,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 - (void)testKeepsTrackOfLimboDocuments {
   FSTQuery *query = [self queryForMessages];
-  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:[FSTDocumentKeySet keySet]];
+  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:DocumentKeySet{}];
 
   FSTDocument *doc1 = FSTTestDoc("rooms/eros/messages/0", 0, @{}, NO);
   FSTDocument *doc2 = FSTTestDoc("rooms/eros/messages/1", 0, @{}, NO);
@@ -339,8 +340,8 @@ NS_ASSUME_NONNULL_BEGIN
 
   // Unlike other cases, here the view is initialized with a set of previously synced documents
   // which happens when listening to a previously listened-to query.
-  FSTView *view = [[FSTView alloc] initWithQuery:query
-                                 remoteDocuments:FSTTestDocKeySet(@[ doc1.key, doc2.key ])];
+  FSTView *view =
+      [[FSTView alloc] initWithQuery:query remoteDocuments:DocumentKeySet{doc1.key, doc2.key}];
 
   FSTTargetChange *markCurrent =
       [FSTTargetChange changeWithDocuments:@[]
@@ -361,7 +362,7 @@ NS_ASSUME_NONNULL_BEGIN
   FSTQuery *query = [[self queryForMessages] queryBySettingLimit:2];
   FSTDocument *doc1 = FSTTestDoc("rooms/eros/messages/0", 0, @{}, NO);
   FSTDocument *doc2 = FSTTestDoc("rooms/eros/messages/1", 0, @{}, NO);
-  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:[FSTDocumentKeySet keySet]];
+  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:DocumentKeySet{}];
 
   // Start with a full view.
   FSTViewDocumentChanges *changes =
@@ -394,7 +395,7 @@ NS_ASSUME_NONNULL_BEGIN
   FSTDocument *doc1 = FSTTestDoc("rooms/eros/messages/0", 0, @{ @"order" : @1 }, NO);
   FSTDocument *doc2 = FSTTestDoc("rooms/eros/messages/1", 0, @{ @"order" : @2 }, NO);
   FSTDocument *doc3 = FSTTestDoc("rooms/eros/messages/2", 0, @{ @"order" : @3 }, NO);
-  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:[FSTDocumentKeySet keySet]];
+  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:DocumentKeySet{}];
 
   // Start with a full view.
   FSTViewDocumentChanges *changes =
@@ -430,7 +431,7 @@ NS_ASSUME_NONNULL_BEGIN
   FSTDocument *doc3 = FSTTestDoc("rooms/eros/messages/2", 0, @{ @"order" : @3 }, NO);
   FSTDocument *doc4 = FSTTestDoc("rooms/eros/messages/3", 0, @{ @"order" : @4 }, NO);
   FSTDocument *doc5 = FSTTestDoc("rooms/eros/messages/4", 0, @{ @"order" : @5 }, NO);
-  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:[FSTDocumentKeySet keySet]];
+  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:DocumentKeySet{}];
 
   // Start with a full view.
   FSTViewDocumentChanges *changes =
@@ -460,7 +461,7 @@ NS_ASSUME_NONNULL_BEGIN
   FSTDocument *doc3 = FSTTestDoc("rooms/eros/messages/2", 0, @{ @"order" : @3 }, NO);
   FSTDocument *doc4 = FSTTestDoc("rooms/eros/messages/3", 0, @{ @"order" : @4 }, NO);
   FSTDocument *doc5 = FSTTestDoc("rooms/eros/messages/4", 0, @{ @"order" : @5 }, NO);
-  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:[FSTDocumentKeySet keySet]];
+  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:DocumentKeySet{}];
 
   // Start with a full view.
   FSTViewDocumentChanges *changes =
@@ -483,7 +484,7 @@ NS_ASSUME_NONNULL_BEGIN
   FSTQuery *query = [[self queryForMessages] queryBySettingLimit:2];
   FSTDocument *doc1 = FSTTestDoc("rooms/eros/messages/0", 0, @{}, NO);
   FSTDocument *doc2 = FSTTestDoc("rooms/eros/messages/1", 0, @{}, NO);
-  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:[FSTDocumentKeySet keySet]];
+  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:DocumentKeySet{}];
 
   // Start with a full view.
   FSTViewDocumentChanges *changes =
@@ -506,7 +507,7 @@ NS_ASSUME_NONNULL_BEGIN
   FSTQuery *query = [[self queryForMessages] queryBySettingLimit:20];
   FSTDocument *doc1 = FSTTestDoc("rooms/eros/messages/0", 0, @{}, NO);
   FSTDocument *doc2 = FSTTestDoc("rooms/eros/messages/1", 0, @{}, NO);
-  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:[FSTDocumentKeySet keySet]];
+  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:DocumentKeySet{}];
 
   FSTViewDocumentChanges *changes =
       [view computeChangesWithDocuments:FSTTestDocUpdates(@[ doc1, doc2 ])];
@@ -528,7 +529,7 @@ NS_ASSUME_NONNULL_BEGIN
   FSTQuery *query = [[self queryForMessages] queryBySettingLimit:2];
   FSTDocument *doc1 = FSTTestDoc("rooms/eros/messages/0", 0, @{}, NO);
   FSTDocument *doc2 = FSTTestDoc("rooms/eros/messages/1", 0, @{}, NO);
-  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:[FSTDocumentKeySet keySet]];
+  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:DocumentKeySet{}];
 
   // Start with a full view.
   FSTViewDocumentChanges *changes =
@@ -551,69 +552,69 @@ NS_ASSUME_NONNULL_BEGIN
   FSTQuery *query = [self queryForMessages];
   FSTDocument *doc1 = FSTTestDoc("rooms/eros/messages/0", 0, @{}, NO);
   FSTDocument *doc2 = FSTTestDoc("rooms/eros/messages/1", 0, @{}, NO);
-  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:[FSTDocumentKeySet keySet]];
+  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:DocumentKeySet{}];
 
   // Start with a full view.
   FSTViewDocumentChanges *changes =
       [view computeChangesWithDocuments:FSTTestDocUpdates(@[ doc1, doc2 ])];
   [view applyChangesToDocuments:changes];
-  XCTAssertEqualObjects(changes.mutatedKeys, FSTTestDocKeySet(@[]));
+  XCTAssertEqual(changes.mutatedKeys, DocumentKeySet{});
 
   FSTDocument *doc3 = FSTTestDoc("rooms/eros/messages/2", 0, @{}, YES);
   changes = [view computeChangesWithDocuments:FSTTestDocUpdates(@[ doc3 ])];
-  XCTAssertEqualObjects(changes.mutatedKeys, FSTTestDocKeySet(@[ doc3.key ]));
+  XCTAssertEqual(changes.mutatedKeys, DocumentKeySet{doc3.key});
 }
 
 - (void)testRemovesKeysFromMutatedKeysWhenNewDocHasNoLocalChanges {
   FSTQuery *query = [self queryForMessages];
   FSTDocument *doc1 = FSTTestDoc("rooms/eros/messages/0", 0, @{}, NO);
   FSTDocument *doc2 = FSTTestDoc("rooms/eros/messages/1", 0, @{}, YES);
-  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:[FSTDocumentKeySet keySet]];
+  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:DocumentKeySet{}];
 
   // Start with a full view.
   FSTViewDocumentChanges *changes =
       [view computeChangesWithDocuments:FSTTestDocUpdates(@[ doc1, doc2 ])];
   [view applyChangesToDocuments:changes];
-  XCTAssertEqualObjects(changes.mutatedKeys, FSTTestDocKeySet(@[ doc2.key ]));
+  XCTAssertEqual(changes.mutatedKeys, (DocumentKeySet{doc2.key}));
 
   FSTDocument *doc2Prime = FSTTestDoc("rooms/eros/messages/1", 0, @{}, NO);
   changes = [view computeChangesWithDocuments:FSTTestDocUpdates(@[ doc2Prime ])];
   [view applyChangesToDocuments:changes];
-  XCTAssertEqualObjects(changes.mutatedKeys, FSTTestDocKeySet(@[]));
+  XCTAssertEqual(changes.mutatedKeys, DocumentKeySet{});
 }
 
 - (void)testRemembersLocalMutationsFromPreviousSnapshot {
   FSTQuery *query = [self queryForMessages];
   FSTDocument *doc1 = FSTTestDoc("rooms/eros/messages/0", 0, @{}, NO);
   FSTDocument *doc2 = FSTTestDoc("rooms/eros/messages/1", 0, @{}, YES);
-  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:[FSTDocumentKeySet keySet]];
+  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:DocumentKeySet{}];
 
   // Start with a full view.
   FSTViewDocumentChanges *changes =
       [view computeChangesWithDocuments:FSTTestDocUpdates(@[ doc1, doc2 ])];
   [view applyChangesToDocuments:changes];
-  XCTAssertEqualObjects(changes.mutatedKeys, FSTTestDocKeySet(@[ doc2.key ]));
+  XCTAssertEqual(changes.mutatedKeys, (DocumentKeySet{doc2.key}));
 
   FSTDocument *doc3 = FSTTestDoc("rooms/eros/messages/2", 0, @{}, NO);
   changes = [view computeChangesWithDocuments:FSTTestDocUpdates(@[ doc3 ])];
   [view applyChangesToDocuments:changes];
-  XCTAssertEqualObjects(changes.mutatedKeys, FSTTestDocKeySet(@[ doc2.key ]));
+  XCTAssertEqual(changes.mutatedKeys, (DocumentKeySet{doc2.key}));
 }
 
 - (void)testRemembersLocalMutationsFromPreviousCallToComputeChangesWithDocuments {
   FSTQuery *query = [self queryForMessages];
   FSTDocument *doc1 = FSTTestDoc("rooms/eros/messages/0", 0, @{}, NO);
   FSTDocument *doc2 = FSTTestDoc("rooms/eros/messages/1", 0, @{}, YES);
-  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:[FSTDocumentKeySet keySet]];
+  FSTView *view = [[FSTView alloc] initWithQuery:query remoteDocuments:DocumentKeySet{}];
 
   // Start with a full view.
   FSTViewDocumentChanges *changes =
       [view computeChangesWithDocuments:FSTTestDocUpdates(@[ doc1, doc2 ])];
-  XCTAssertEqualObjects(changes.mutatedKeys, FSTTestDocKeySet(@[ doc2.key ]));
+  XCTAssertEqual(changes.mutatedKeys, (DocumentKeySet{doc2.key}));
 
   FSTDocument *doc3 = FSTTestDoc("rooms/eros/messages/2", 0, @{}, NO);
   changes = [view computeChangesWithDocuments:FSTTestDocUpdates(@[ doc3 ]) previousChanges:changes];
-  XCTAssertEqualObjects(changes.mutatedKeys, FSTTestDocKeySet(@[ doc2.key ]));
+  XCTAssertEqual(changes.mutatedKeys, (DocumentKeySet{doc2.key}));
 }
 
 @end