GDT: Retry uploading batches failed to upload before the app termination (#5942)

* GDTCCTUploaderTest: test a lost batch upload retry

* GDTCCTUploader: refactoring to prepare for lost batches uploading

* GDTCCTUploader: Upload previously batched events first

* Fix GDTCCTTestStorage

* Refactor GDTCCTUploaderTest

* GDTCORFlatFileStorageTest: batch tests

* GDTCORFlatFileStorage: refactor removeBatchWithID to prepare for eventsForbatchID

* eventsInBatchWithID implementation

* Fix tests

* Uploader fix for empty batch state

* GDTCORUploadCoordinator: high priority targets

* style

* GDTCCTUploaderTest

* GDTCCTUploaderTest: cleanup

* Cleanup and API docs.

* GDTCORUploadCoordinator: revert high priority targets

* GDTCCTUploader: make sure GDTCOREventQoSFast is part of a regular batch as well.

* Cleanup

* GDTCCTUploader: don't report ready for upload until there are events.

* GDTCCTUploaderTest: move failed batch back to the queue

* GDTCORFlatFileStorage: removeBatchWithID with deleteEvents==NO

* GDTCORFlatFileStorage: remove batch directory

* style

* GDTCORFlatFileStorage: comments and debug logs

* formatting

* GDTCCTUploaderTest: recover tests

* GDTCCTTestServer: support for async request handler

* GDTCCTUploaderTest: ongoing request tests

* GDTCORStorageProtocol: remove redundant `eventsInBatchWithID` method.

* GDTCORFlatFileStorageTest: `removeBatchWithID` tests

* Cleanup

* GDTCORFlatFileStorage: cleanup

* GDTCORFlatFileStorageTest: better coverage and cleanup

* Comments and improvements

* GDTCCTUploaderTest: reduce code duplication

* GDTCCTUploaderTest: conditions tests

* GDTCCTUploader: fix next request wait time

* run ./scripts/style.sh

Author: maksymmalyhin

GoogleDataTransport.podspec

@@ -125,13 +125,13 @@ Shared library for iOS SDK data transport needs.
     end
   end
 
-  common_test_sources = ['GoogleDataTransport/GDTCCTTests/Common/**/*.{h,m}']
+  common_cct_test_sources = ['GoogleDataTransport/GDTCCTTests/Common/**/*.{h,m}']
 
   # Test specs
   s.test_spec 'CCT-Tests-Unit' do |test_spec|
     test_spec.platforms = {:ios => '8.0', :osx => '10.11', :tvos => '10.0'}
     test_spec.requires_app_host = false
-    test_spec.source_files = ['GoogleDataTransport/GDTCCTTests/Unit/**/*.{h,m}'] + common_test_sources
+    test_spec.source_files = ['GoogleDataTransport/GDTCCTTests/Unit/**/*.{h,m}'] + common_cct_test_sources + common_test_sources
     test_spec.resources = ['GoogleDataTransport/GDTCCTTests/Data/**/*']
     test_spec.pod_target_xcconfig = header_search_paths
     test_spec.dependency 'GCDWebServer'
@@ -140,7 +140,7 @@ Shared library for iOS SDK data transport needs.
   s.test_spec 'CCT-Tests-Integration' do |test_spec|
     test_spec.platforms = {:ios => '8.0', :osx => '10.11', :tvos => '10.0'}
     test_spec.requires_app_host = false
-    test_spec.source_files = ['GoogleDataTransport/GDTCCTTests/Integration/**/*.{h,m}'] + common_test_sources
+    test_spec.source_files = ['GoogleDataTransport/GDTCCTTests/Integration/**/*.{h,m}'] + common_cct_test_sources
     test_spec.resources = ['GoogleDataTransport/GDTCCTTests/Data/**/*']
     test_spec.pod_target_xcconfig = header_search_paths
   end
@@ -152,7 +152,7 @@ Shared library for iOS SDK data transport needs.
       test_spec.requires_app_host = true
       test_spec.app_host_name = 'GoogleDataTransport/CCTTestApp'
       test_spec.dependency 'GoogleDataTransport/CCTTestApp'
-      test_spec.source_files = ['GoogleDataTransport/GDTCCTTests/Monkey/**/*.{swift}'] + common_test_sources
+      test_spec.source_files = ['GoogleDataTransport/GDTCCTTests/Monkey/**/*.{swift}'] + common_cct_test_sources
       test_spec.info_plist = {
         'GDT_MONKEYTEST' => '1'
       }

GoogleDataTransport/GDTCCTLibrary/GDTCCTUploader.m

@@ -15,9 +15,43 @@
  */
 
 #import <Foundation/Foundation.h>
+#import <XCTest/XCTest.h>
 
 #import "GoogleDataTransport/GDTCORLibrary/Public/GDTCORStorageProtocol.h"
 
+NS_ASSUME_NONNULL_BEGIN
+
+typedef void (^GDTCCTTestStorageBatchHandler)(GDTCORStorageEventSelector *_Nullable eventSelector,
+                                              NSDate *_Nullable expiration,
+                                              GDTCORStorageBatchBlock _Nullable completion);
+
+typedef void (^GDTCCTTestStorageHasEventsCompletion)(BOOL hasEvents);
+typedef void (^GDTCCTTestStorageHasEventsHandler)(GDTCORTarget target,
+                                                  GDTCCTTestStorageHasEventsCompletion completion);
+
 @interface GDTCCTTestStorage : NSObject <GDTCORStorageProtocol>
 
+#pragma mark - Method call expectations.
+
+@property(nonatomic, nullable) XCTestExpectation *batchWithEventSelectorExpectation;
+@property(nonatomic, nullable) XCTestExpectation *removeBatchAndDeleteEventsExpectation;
+@property(nonatomic, nullable) XCTestExpectation *removeBatchWithoutDeletingEventsExpectation;
+@property(nonatomic, nullable) XCTestExpectation *batchIDsForTargetExpectation;
+
+#pragma mark - Blocks to provide custom implementations for the methods.
+
+/// A block to override `batchWithEventSelector:batchExpiration:onComplete:` implementation.
+@property(nonatomic, copy, nullable) GDTCCTTestStorageBatchHandler batchWithEventSelectorHandler;
+/// A block to override `hasEventsForTarget:onComplete:` implementation.
+@property(nonatomic, copy, nullable) GDTCCTTestStorageHasEventsHandler hasEventsForTargetHandler;
+
+#pragma mark - Default test implementations
+
+/// Default test implementation for `batchWithEventSelector:batchExpiration:onComplete:`  method.
+- (void)defaultBatchWithEventSelector:(nonnull GDTCORStorageEventSelector *)eventSelector
+                      batchExpiration:(nonnull NSDate *)expiration
+                           onComplete:(nonnull GDTCORStorageBatchBlock)onComplete;
+
 @end
+
+NS_ASSUME_NONNULL_END

GoogleDataTransport/GDTCCTTests/Common/TestStorage/GDTCCTTestStorage.h

@@ -26,12 +26,17 @@ @implementation GDTCCTTestStorage {
   NSMutableDictionary<NSNumber *, NSSet<GDTCOREvent *> *> *_batches;
 }
 
+- (instancetype)init {
+  self = [super init];
+  if (self) {
+    _storedEvents = [[NSMutableDictionary alloc] init];
+    _batches = [[NSMutableDictionary alloc] init];
+  }
+  return self;
+}
+
 - (void)storeEvent:(GDTCOREvent *)event
         onComplete:(void (^_Nullable)(BOOL wasWritten, NSError *_Nullable))completion {
-  static dispatch_once_t onceToken;
-  dispatch_once(&onceToken, ^{
-    self->_storedEvents = [[NSMutableDictionary alloc] init];
-  });
   _storedEvents[event.eventID] = event;
   if (completion) {
     completion(YES, nil);
@@ -44,28 +49,29 @@ - (void)removeEvents:(NSSet<NSString *> *)eventIDs {
 
 - (void)batchWithEventSelector:(nonnull GDTCORStorageEventSelector *)eventSelector
                batchExpiration:(nonnull NSDate *)expiration
-                    onComplete:
-                        (nonnull void (^)(NSNumber *_Nullable batchID,
-                                          NSSet<GDTCOREvent *> *_Nullable events))onComplete {
-  static NSInteger count = 0;
-  NSNumber *batchID = @(count);
-  count++;
-  static dispatch_once_t onceToken;
-  dispatch_once(&onceToken, ^{
-    self->_batches = [[NSMutableDictionary alloc] init];
-  });
-  NSSet<GDTCOREvent *> *batchEvents = [NSSet setWithArray:[_storedEvents allValues]];
-  _batches[batchID] = batchEvents;
-  [_storedEvents removeAllObjects];
-  if (onComplete) {
-    onComplete(batchID, batchEvents);
+                    onComplete:(nonnull GDTCORStorageBatchBlock)onComplete {
+  if (self.batchWithEventSelectorHandler) {
+    self.batchWithEventSelectorHandler(eventSelector, expiration, onComplete);
+  } else {
+    [self defaultBatchWithEventSelector:eventSelector
+                        batchExpiration:expiration
+                             onComplete:onComplete];
   }
 }
 
 - (void)removeBatchWithID:(nonnull NSNumber *)batchID
              deleteEvents:(BOOL)deleteEvents
                onComplete:(void (^_Nullable)(void))onComplete {
-  [_batches removeObjectForKey:batchID];
+  if (deleteEvents) {
+    [_batches removeObjectForKey:batchID];
+    [self.removeBatchAndDeleteEventsExpectation fulfill];
+  } else {
+    for (GDTCOREvent *batchedEvent in _batches[batchID]) {
+      _storedEvents[batchedEvent.eventID] = batchedEvent;
+    }
+    [self.removeBatchWithoutDeletingEventsExpectation fulfill];
+  }
+
   if (onComplete) {
     onComplete();
   }
@@ -95,7 +101,9 @@ - (void)removeLibraryDataForKey:(nonnull NSString *)key
 }
 
 - (void)hasEventsForTarget:(GDTCORTarget)target onComplete:(nonnull void (^)(BOOL))onComplete {
-  if (onComplete) {
+  if (self.hasEventsForTargetHandler) {
+    self.hasEventsForTargetHandler(target, onComplete);
+  } else if (onComplete) {
     onComplete(NO);
   }
 }
@@ -105,12 +113,32 @@ - (void)storageSizeWithCallback:(void (^)(uint64_t storageSize))onComplete {
 
 - (void)batchIDsForTarget:(GDTCORTarget)target
                onComplete:(nonnull void (^)(NSSet<NSNumber *> *_Nullable))onComplete {
+  [self.batchIDsForTargetExpectation fulfill];
   if (onComplete) {
-    onComplete(nil);
+    onComplete([NSSet setWithArray:[self->_batches allKeys]]);
   }
 }
 
 - (void)checkForExpirations {
 }
 
+#pragma mark - Default Implementations
+
+- (void)defaultBatchWithEventSelector:(nonnull GDTCORStorageEventSelector *)eventSelector
+                      batchExpiration:(nonnull NSDate *)expiration
+                           onComplete:(nonnull GDTCORStorageBatchBlock)onComplete {
+  static NSInteger count = 0;
+  NSNumber *batchID = @(count);
+  count++;
+
+  NSSet<GDTCOREvent *> *batchEvents = [NSSet setWithArray:[_storedEvents allValues]];
+  _batches[batchID] = batchEvents;
+  [_storedEvents removeAllObjects];
+
+  [self.batchWithEventSelectorExpectation fulfill];
+  if (onComplete) {
+    onComplete(batchID, batchEvents);
+  }
+}
+
 @end