[in_app_purchase_storekit] backfill native tests for more complete test coverage (#6209)

Added more native tests for more complete test coverage.
Fixes flutter/flutter#143889

## Pre-launch Checklist

- [x] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [x] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [x] I read and followed the [relevant style guides] and ran the
auto-formatter. (Unlike the flutter/flutter repo, the flutter/packages
repo does use `dart format`.)
- [x] I signed the [CLA].
- [x] The title of the PR starts with the name of the package surrounded
by square brackets, e.g. `[shared_preferences]`
- [x] I listed at least one issue that this PR fixes in the description
above.
- [x] I updated `pubspec.yaml` with an appropriate new version according
to the [pub versioning philosophy], or this PR is [exempt from version
changes].
- [x] I updated `CHANGELOG.md` to add a description of the change,
[following repository CHANGELOG style].
- [x] I updated/added relevant documentation (doc comments with `///`).
- [x] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [x] All existing and new tests are passing.

Author: LouiseHsu

packages/in_app_purchase/in_app_purchase_storekit/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.3.13
+
+* Added new native tests for more complete test coverage.
+
 ## 0.3.12+1
 
 * Fixes type of error code returned from native code in SKReceiptManager.retrieveReceiptData.

packages/in_app_purchase/in_app_purchase_storekit/darwin/Classes/InAppPurchasePlugin+TestOnly.h

@@ -0,0 +1,32 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#import <StoreKit/StoreKit.h>
+#import "FIAPRequestHandler.h"
+#import "InAppPurchasePlugin.h"
+
+@interface InAppPurchasePlugin ()
+
+// Holding strong references to FIAPRequestHandlers. Remove the handlers from the set after
+// the request is finished.
+@property(strong, nonatomic, readonly) NSMutableSet *requestHandlers;
+
+// Callback channel to dart used for when a function from the transaction observer is triggered.
+@property(strong, nonatomic) FlutterMethodChannel *transactionObserverCallbackChannel;
+
+// Callback channel to dart used for when a function from the transaction observer is triggered.
+@property(copy, nonatomic) FIAPRequestHandler * (^handlerFactory)(SKRequest *);
+
+// Convenience initializer with dependancy injection
+- (instancetype)initWithReceiptManager:(FIAPReceiptManager *)receiptManager
+                        handlerFactory:(FIAPRequestHandler * (^)(SKRequest *))handlerFactory;
+
+// Transaction observer methods
+- (void)handleTransactionsUpdated:(NSArray<SKPaymentTransaction *> *)transactions;
+- (void)handleTransactionsRemoved:(NSArray<SKPaymentTransaction *> *)transactions;
+- (void)handleTransactionRestoreFailed:(NSError *)error;
+- (void)restoreCompletedTransactionsFinished;
+- (BOOL)shouldAddStorePayment:(SKPayment *)payment product:(SKProduct *)product;
+
+@end

packages/in_app_purchase/in_app_purchase_storekit/darwin/Classes/InAppPurchasePlugin.m

@@ -9,20 +9,14 @@
 #import "FIAPReceiptManager.h"
 #import "FIAPRequestHandler.h"
 #import "FIAPaymentQueueHandler.h"
+#import "InAppPurchasePlugin+TestOnly.h"
 
 @interface InAppPurchasePlugin ()
 
-// Holding strong references to FIAPRequestHandlers. Remove the handlers from the set after
-// the request is finished.
-@property(strong, nonatomic, readonly) NSMutableSet *requestHandlers;
-
 // After querying the product, the available products will be saved in the map to be used
 // for purchase.
 @property(strong, nonatomic, readonly) NSMutableDictionary *productsCache;
 
-// Callback channel to dart used for when a function from the transaction observer is triggered.
-@property(strong, nonatomic, readonly) FlutterMethodChannel *transactionObserverCallbackChannel;
-
 // Callback channel to dart used for when a function from the payment queue delegate is triggered.
 @property(strong, nonatomic, readonly) FlutterMethodChannel *paymentQueueDelegateCallbackChannel;
 @property(strong, nonatomic, readonly) NSObject<FlutterPluginRegistrar> *registrar;
@@ -52,6 +46,16 @@ - (instancetype)initWithReceiptManager:(FIAPReceiptManager *)receiptManager {
   _receiptManager = receiptManager;
   _requestHandlers = [NSMutableSet new];
   _productsCache = [NSMutableDictionary new];
+  _handlerFactory = ^FIAPRequestHandler *(SKRequest *request) {
+    return [[FIAPRequestHandler alloc] initWithRequest:request];
+  };
+  return self;
+}
+
+- (instancetype)initWithReceiptManager:(FIAPReceiptManager *)receiptManager
+                        handlerFactory:(FIAPRequestHandler * (^)(SKRequest *))handlerFactory {
+  self = [self initWithReceiptManager:receiptManager];
+  _handlerFactory = [handlerFactory copy];
   return self;
 }
 
@@ -117,7 +121,7 @@ - (void)startProductRequestProductIdentifiers:(NSArray<NSString *> *)productIden
                                                         FlutterError *_Nullable))completion {
   SKProductsRequest *request =
       [self getProductRequestWithIdentifiers:[NSSet setWithArray:productIdentifiers]];
-  FIAPRequestHandler *handler = [[FIAPRequestHandler alloc] initWithRequest:request];
+  FIAPRequestHandler *handler = self.handlerFactory(request);
   [self.requestHandlers addObject:handler];
   __weak typeof(self) weakSelf = self;
 
@@ -271,7 +275,7 @@ - (void)refreshReceiptReceiptProperties:(nullable NSDictionary *)receiptProperti
     request = [self getRefreshReceiptRequest:nil];
   }
 
-  FIAPRequestHandler *handler = [[FIAPRequestHandler alloc] initWithRequest:request];
+  FIAPRequestHandler *handler = self.handlerFactory(request);
   [self.requestHandlers addObject:handler];
   __weak typeof(self) weakSelf = self;
   [handler startProductRequestWithCompletionHandler:^(SKProductsResponse *_Nullable response,
@@ -282,6 +286,7 @@ - (void)refreshReceiptReceiptProperties:(nullable NSDictionary *)receiptProperti
                                          message:error.localizedDescription
                                          details:error.description];
       completion(requestError);
+      return;
     }
     completion(nil);
     [weakSelf.requestHandlers removeObject:handler];