Adding onSnapshotsInSync (not public)

Firestore/Example/Tests/Integration/API/FIRDatabaseTests.mm

@@ -531,6 +531,42 @@ - (void)testAddingToACollectionYieldsTheCorrectDocumentReference {
   [self awaitExpectations];
 }
 
+- (void)testSnapshotsInSyncListenerFiresAfterListenersInSync {
+  FIRCollectionReference *coll = [self.db collectionWithPath:@"collection"];
+  FIRDocumentReference *ref = [coll addDocumentWithData:@{@"foo" : @1}];
+  NSMutableArray<NSString *> *events = [NSMutableArray array];
+
+  XCTestExpectation *gotInitialSnapshot = [self expectationWithDescription:@"gotInitialSnapshot"];
+  __block bool setupComplete = false;
+  [ref addSnapshotListener:^(FIRDocumentSnapshot *snapshot, NSError *error) {
+    XCTAssertNil(error);
+    [events addObject:@"doc"];
+    // Wait for the initial event from the backend so that we know we'll get exactly one snapshot
+    // event for our local write below.
+    if (!setupComplete) {
+      setupComplete = true;
+      [gotInitialSnapshot fulfill];
+    }
+  }];
+
+  [self awaitExpectations];
+  [events removeAllObjects];
+
+  XCTestExpectation *done = [self expectationWithDescription:@"SnapshotsInSyncListenerDone"];
+  [ref.firestore addSnapshotsInSyncListener:^() {
+    [events addObject:@"snapshots-in-sync"];
+    if ([events count] == 3) {
+      // We should have an initial snapshots-in-sync event, then a snapshot event
+      // for set(), then another event to indicate we're in sync again.
+      NSArray<NSString *> *expected = @[ @"snapshots-in-sync", @"doc", @"snapshots-in-sync" ];
+      XCTAssertEqualObjects(events, expected);
+      [done fulfill];
+    }
+  }];
+
+  [self writeDocumentRef:ref data:@{@"foo" : @3}];
+}
+
 - (void)testListenCanBeCalledMultipleTimes {
   FIRCollectionReference *coll = [self.db collectionWithPath:@"collection"];
   FIRDocumentReference *doc = [coll documentWithAutoID];

Firestore/Example/Tests/SpecTests/FSTSpecTests.mm

@@ -278,6 +278,14 @@ - (void)doDelete:(NSString *)key {
   [self.driver writeUserMutation:FSTTestDeleteMutation(key)];
 }
 
+- (void)doAddSnapshotsInSyncListener {
+  [self.driver addSnapshotsInSyncListener];
+}
+
+- (void)doRemoveSnapshotsInSyncListener {
+  [self.driver removeSnapshotsInSyncListener];
+}
+
 - (void)doWatchAck:(NSArray<NSNumber *> *)ackedTargets {
   WatchTargetChange change{WatchTargetChangeState::Added, ConvertTargetsArray(ackedTargets)};
   [self.driver receiveWatchChange:change snapshotVersion:SnapshotVersion::None()];
@@ -479,6 +487,10 @@ - (void)doStep:(NSDictionary *)step {
     [self doPatch:step[@"userPatch"]];
   } else if (step[@"userDelete"]) {
     [self doDelete:step[@"userDelete"]];
+  } else if (step[@"addSnapshotsInSyncListener"]) {
+    [self doAddSnapshotsInSyncListener];
+  } else if (step[@"removeSnapshotsInSyncListener"]) {
+    [self doRemoveSnapshotsInSyncListener];
   } else if (step[@"drainQueue"]) {
     [self doDrainQueue];
   } else if (step[@"watchAck"]) {
@@ -651,6 +663,11 @@ - (void)validateStateExpectations:(nullable NSDictionary *)expected {
   [self validateActiveTargets];
 }
 
+- (void)validateSnapshotsInSyncEvents:(int)expectedSnapshotInSyncEvents {
+  XCTAssertEqual(expectedSnapshotInSyncEvents, [self.driver snapshotsInSyncEvents]);
+  [self.driver resetSnapshotsInSyncEvents];
+}
+
 - (void)validateUserCallbacks:(nullable NSDictionary *)expected {
   NSDictionary *expectedCallbacks = expected[@"userCallbacks"];
   NSArray<NSString *> *actualAcknowledgedDocs =
@@ -728,6 +745,8 @@ - (void)runSpecTestSteps:(NSArray *)steps config:(NSDictionary *)config {
       [self doStep:step];
       [self validateStepExpectations:step[@"expect"]];
       [self validateStateExpectations:step[@"stateExpect"]];
+      int expectedSnapshotsInSyncEvents = [step[@"expectedSnapshotsInSyncEvents"] intValue];
+      [self validateSnapshotsInSyncEvents:expectedSnapshotsInSyncEvents];
     }
     [self.driver validateUsage];
   } @finally {

Firestore/Example/Tests/SpecTests/FSTSyncEngineTestDriver.h

@@ -22,6 +22,7 @@
 #include <vector>
 
 #include "Firestore/core/src/firebase/firestore/auth/user.h"
+#include "Firestore/core/src/firebase/firestore/core/event_listener.h"
 #include "Firestore/core/src/firebase/firestore/core/query.h"
 #include "Firestore/core/src/firebase/firestore/core/view_snapshot.h"
 #include "Firestore/core/src/firebase/firestore/local/query_data.h"
@@ -32,6 +33,7 @@
 #include "Firestore/core/src/firebase/firestore/model/types.h"
 #include "Firestore/core/src/firebase/firestore/remote/watch_change.h"
 #include "Firestore/core/src/firebase/firestore/util/async_queue.h"
+#include "Firestore/core/src/firebase/firestore/util/empty.h"
 
 namespace firebase {
 namespace firestore {
@@ -311,6 +313,26 @@ typedef std::unordered_map<firebase::firestore::auth::User,
 /** The current user for the FSTSyncEngine; determines which mutation queue is active. */
 @property(nonatomic, assign, readonly) const firebase::firestore::auth::User &currentUser;
 
+/**
+ * The number of snapshots-in-sync events that have been received.
+ */
+@property(nonatomic, readonly) int snapshotsInSyncEvents;
+
+- (void)incrementSnapshotsInSyncEvents;
+
+- (void)resetSnapshotsInSyncEvents;
+
+/**
+ * Adds a snpahots-in-sync listener to the event manager and keeps track of it so that it
+ * can be easily removed later.
+ */
+- (void)addSnapshotsInSyncListener;
+
+/**
+ * Removes the snapshots-in-sync listener from the event manager.
+ */
+- (void)removeSnapshotsInSyncListener;
+
 /** The set of active targets as observed on the watch stream. */
 - (const std::unordered_map<firebase::firestore::model::TargetId, local::QueryData> &)activeTargets;
 

Firestore/Example/Tests/SpecTests/FSTSyncEngineTestDriver.mm

@@ -56,6 +56,7 @@
 using firebase::firestore::auth::HashUser;
 using firebase::firestore::auth::User;
 using firebase::firestore::core::DatabaseInfo;
+using firebase::firestore::core::EventListener;
 using firebase::firestore::core::EventManager;
 using firebase::firestore::core::ListenOptions;
 using firebase::firestore::core::Query;
@@ -78,6 +79,7 @@
 using firebase::firestore::remote::WatchChange;
 using firebase::firestore::util::AsyncQueue;
 using firebase::firestore::util::DelayedConstructor;
+using firebase::firestore::util::Empty;
 using firebase::firestore::util::ExecutorLibdispatch;
 using firebase::firestore::util::MakeNSError;
 using firebase::firestore::util::MakeNSString;
@@ -170,7 +172,10 @@ @implementation FSTSyncEngineTestDriver {
   DatabaseInfo _databaseInfo;
   User _currentUser;
 
+  std::vector<std::shared_ptr<EventListener<Empty>>> _snapshotsInSyncListeners;
   std::shared_ptr<MockDatastore> _datastore;
+
+  int _snapshotsInSyncEvents;
 }
 
 - (instancetype)initWithPersistence:(std::unique_ptr<Persistence>)persistence {
@@ -246,6 +251,34 @@ - (void)drainQueue {
   return _currentUser;
 }
 
+- (void)incrementSnapshotsInSyncEvents {
+  _snapshotsInSyncEvents += 1;
+}
+
+- (void)resetSnapshotsInSyncEvents {
+  _snapshotsInSyncEvents = 0;
+}
+
+- (void)addSnapshotsInSyncListener {
+  std::shared_ptr<EventListener<Empty>> eventListener = EventListener<Empty>::Create(
+      [self](const StatusOr<Empty> &) { [self incrementSnapshotsInSyncEvents]; });
+  _snapshotsInSyncListeners.push_back(eventListener);
+  _eventManager->AddSnapshotsInSyncListener(eventListener);
+}
+
+- (void)removeSnapshotsInSyncListener {
+  if (_snapshotsInSyncListeners.empty()) {
+    HARD_FAIL("There must be a listener to unlisten to");
+  } else {
+    _eventManager->RemoveSnapshotsInSyncListener(_snapshotsInSyncListeners.back());
+    _snapshotsInSyncListeners.pop_back();
+  }
+}
+
+- (int)snapshotsInSyncEvents {
+  return _snapshotsInSyncEvents;
+}
+
 - (void)start {
   _workerQueue->EnqueueBlocking([&] {
     _localStore->Start();