Merge pull request #478 from morganchen12/master

Fix bad loop behavior on invalidation in FUIArray, add tests

Author: morganchen12

FirebaseDatabaseUI/FUIArray.m

@@ -161,7 +161,7 @@ - (void)invalidate {
 
   // Remove all values on invalidation.
   [self didUpdate];
-  for (NSInteger i = 0; i < self.snapshots.count; i++) {
+  for (NSInteger i = 0; i < self.snapshots.count; /* no i++ since we modify the array instead*/ ) {
     FIRDataSnapshot *current = self.snapshots[i];
 
     [self.snapshots removeObjectAtIndex:i];
@@ -269,7 +269,7 @@ - (id)objectAtIndexedSubscript:(NSUInteger)index {
   return [self snapshotAtIndex:index];
 }
 
-- (void)setObject:(id)obj atIndexedSubscript:(NSUInteger)index{
+- (void)setObject:(id)obj atIndexedSubscript:(NSUInteger)index {
   @throw [NSException exceptionWithName:@"FUIArraySetIndexWithSubscript"
                                  reason:@"Setting an object as FUIArray[i] is not supported."
                                userInfo:nil];

FirebaseDatabaseUITests/FUIArrayTest.m

@@ -476,4 +476,13 @@ - (void)testArraySendsMessagesAfterReceivingValueEvent {
   XCTAssert(ended == 1, @"expected array to end updates exactly once");
 }
 
+- (void)testRemovesAllElementsWhenInvalidated {
+  [self.observable populateWithCount:10];
+  [self.firebaseArray invalidate];
+
+  XCTAssert(self.firebaseArray.count == 0,
+            @"Expected array to be empty after invalidation, instead got %ld elements",
+            self.firebaseArray.count);
+}
+
 @end