fix: flaky FIRCLSSettingsTests.m

Crashlytics/Crashlytics/Models/FIRCLSSettings.m

@@ -190,19 +190,15 @@ - (NSDictionary *)loadCacheKey {
 
 - (void)deleteCachedSettings {
   __weak FIRCLSSettings *weakSelf = self;
-#ifndef FIREBASE_IS_NIGHTLY_TESTING
   dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0), ^{
-#endif
     __strong FIRCLSSettings *strongSelf = weakSelf;
     if ([strongSelf.fileManager fileExistsAtPath:strongSelf.fileManager.settingsFilePath]) {
       [strongSelf.fileManager removeItemAtPath:strongSelf.fileManager.settingsFilePath];
     }
     if ([strongSelf.fileManager fileExistsAtPath:strongSelf.fileManager.settingsCacheKeyPath]) {
       [strongSelf.fileManager removeItemAtPath:strongSelf.fileManager.settingsCacheKeyPath];
     }
-#ifndef FIREBASE_IS_NIGHTLY_TESTING
   });
-#endif
 
   @synchronized(self) {
     self.isCacheKeyExpired = YES;

Crashlytics/UnitTests/FIRCLSSettingsTests.m

@@ -76,6 +76,11 @@
 - (void)setUp {
   [super setUp];
 
+  dispatch_sync(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0), ^{
+                    // Drain queue to prevent interference from previous tests.
+                    // This queue is used by `- [FIRCLSSettings deleteCachedSettings]`.
+                });
+
   _fileManager = [[FIRCLSMockFileManager alloc] init];
 
   _appIDModel = [[FABMockApplicationIdentifierModel alloc] init];
@@ -134,7 +139,7 @@
 
   [self.settings cacheSettingsWithGoogleAppID:googleAppID currentTimestamp:currentTimestamp];
 
   [self waitForExpectations:@[ self.fileManager.removeExpectation ] timeout:1];
 }
 
 - (void)reloadFromCacheWithGoogleAppID:(NSString *)googleAppID
@@ -147,7 +152,7 @@
 
   [self.settings reloadFromCacheWithGoogleAppID:googleAppID currentTimestamp:currentTimestamp];
 
   [self waitForExpectations:@[ self.fileManager.removeExpectation ] timeout:5.0];
 }
 
 - (void)testActivatedSettingsCached {