Allow `--use-application-binary` using app-bundles on ios (#17691)

This makes it easier to run ios add2app apps with Flutter run.
diff --git a/packages/flutter_tools/test/application_package_test.dart b/packages/flutter_tools/test/application_package_test.dart
index a2f4856..d4e4ded 100644
--- a/packages/flutter_tools/test/application_package_test.dart
+++ b/packages/flutter_tools/test/application_package_test.dart
@@ -2,15 +2,25 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import 'package:flutter_tools/src/application_package.dart';
-import 'package:test/test.dart';
+import 'dart:convert';
 
+import 'package:flutter_tools/src/application_package.dart';
+import 'package:flutter_tools/src/base/context.dart';
+import 'package:flutter_tools/src/base/file_system.dart';
+import 'package:flutter_tools/src/base/logger.dart';
+import 'package:flutter_tools/src/base/os.dart';
+import 'package:flutter_tools/src/ios/ios_workflow.dart';
+import 'package:test/test.dart';
+import 'package:file/file.dart';
+import 'package:file/memory.dart';
+import 'package:mockito/mockito.dart';
 import 'src/context.dart';
 
 void main() {
   group('ApkManifestData', () {
     testUsingContext('parse sdk', () {
-      final ApkManifestData data = ApkManifestData.parseFromAaptBadging(_aaptData);
+      final ApkManifestData data =
+          ApkManifestData.parseFromAaptBadging(_aaptData);
       expect(data, isNotNull);
       expect(data.packageName, 'io.flutter.gallery');
       expect(data.launchableActivityName, 'io.flutter.app.FlutterActivity');
@@ -28,6 +38,118 @@
       expect(buildableIOSApp.isSwift, true);
     });
   });
+
+  group('PrebuiltIOSApp', () {
+    final Map<Type, Generator> overrides = <Type, Generator>{
+      FileSystem: () => new MemoryFileSystem(),
+      IOSWorkflow: () => new MockIosWorkFlow()
+    };
+    testUsingContext('Error on non-existing file', () {
+      final PrebuiltIOSApp iosApp =
+          new IOSApp.fromPrebuiltApp('not_existing.ipa');
+      expect(iosApp, isNull);
+      final BufferLogger logger = context[Logger];
+      expect(
+        logger.errorText,
+        'File "not_existing.ipa" does not exist. Use an app bundle or an ipa.\n',
+      );
+    }, overrides: overrides);
+    testUsingContext('Error on non-app-bundle folder', () {
+      fs.directory('regular_folder').createSync();
+      final PrebuiltIOSApp iosApp =
+          new IOSApp.fromPrebuiltApp('regular_folder');
+      expect(iosApp, isNull);
+      final BufferLogger logger = context[Logger];
+      expect(
+          logger.errorText, 'Folder "regular_folder" is not an app bundle.\n');
+    }, overrides: overrides);
+    testUsingContext('Error on no info.plist', () {
+      fs.directory('bundle.app').createSync();
+      final PrebuiltIOSApp iosApp = new IOSApp.fromPrebuiltApp('bundle.app');
+      expect(iosApp, isNull);
+      final BufferLogger logger = context[Logger];
+      expect(
+        logger.errorText,
+        'Invalid prebuilt iOS app. Does not contain Info.plist.\n',
+      );
+    }, overrides: overrides);
+    testUsingContext('Error on bad info.plist', () {
+      fs.directory('bundle.app').createSync();
+      fs.file('bundle.app/Info.plist').writeAsStringSync(badPlistData);
+      final PrebuiltIOSApp iosApp = new IOSApp.fromPrebuiltApp('bundle.app');
+      expect(iosApp, isNull);
+      final BufferLogger logger = context[Logger];
+      expect(
+        logger.errorText,
+        contains(
+            'Invalid prebuilt iOS app. Info.plist does not contain bundle identifier\n'),
+      );
+    }, overrides: overrides);
+    testUsingContext('Success with app bundle', () {
+      fs.directory('bundle.app').createSync();
+      fs.file('bundle.app/Info.plist').writeAsStringSync(plistData);
+      final PrebuiltIOSApp iosApp = new IOSApp.fromPrebuiltApp('bundle.app');
+      final BufferLogger logger = context[Logger];
+      expect(logger.errorText, isEmpty);
+      expect(iosApp.bundleDir.path, 'bundle.app');
+      expect(iosApp.id, 'fooBundleId');
+      expect(iosApp.bundleName, 'bundle.app');
+    }, overrides: overrides);
+    testUsingContext('Bad ipa zip-file, no payload dir', () {
+      fs.file('app.ipa').createSync();
+      when(os.unzip(fs.file('app.ipa'), any)).thenAnswer((Invocation _) {});
+      final PrebuiltIOSApp iosApp = new IOSApp.fromPrebuiltApp('app.ipa');
+      expect(iosApp, isNull);
+      final BufferLogger logger = context[Logger];
+      expect(
+        logger.errorText,
+        'Invalid prebuilt iOS ipa. Does not contain a "Payload" directory.\n',
+      );
+    }, overrides: overrides);
+    testUsingContext('Bad ipa zip-file, two app bundles', () {
+      fs.file('app.ipa').createSync();
+      when(os.unzip(any, any)).thenAnswer((Invocation invocation) {
+        final File zipFile = invocation.positionalArguments[0];
+        if (zipFile.path != 'app.ipa') {
+          return null;
+        }
+        final Directory targetDirectory = invocation.positionalArguments[1];
+        final String bundlePath1 =
+            fs.path.join(targetDirectory.path, 'Payload', 'bundle1.app');
+        final String bundlePath2 =
+            fs.path.join(targetDirectory.path, 'Payload', 'bundle2.app');
+        fs.directory(bundlePath1).createSync(recursive: true);
+        fs.directory(bundlePath2).createSync(recursive: true);
+      });
+      final PrebuiltIOSApp iosApp = new IOSApp.fromPrebuiltApp('app.ipa');
+      expect(iosApp, isNull);
+      final BufferLogger logger = context[Logger];
+      expect(logger.errorText,
+          'Invalid prebuilt iOS ipa. Does not contain a single app bundle.\n');
+    }, overrides: overrides);
+    testUsingContext('Success with ipa', () {
+      fs.file('app.ipa').createSync();
+      when(os.unzip(any, any)).thenAnswer((Invocation invocation) {
+        final File zipFile = invocation.positionalArguments[0];
+        if (zipFile.path != 'app.ipa') {
+          return null;
+        }
+        final Directory targetDirectory = invocation.positionalArguments[1];
+        final Directory bundleAppDir = fs.directory(
+            fs.path.join(targetDirectory.path, 'Payload', 'bundle.app'));
+        bundleAppDir.createSync(recursive: true);
+        fs
+            .file(fs.path.join(bundleAppDir.path, 'Info.plist'))
+            .writeAsStringSync(plistData);
+      });
+      final PrebuiltIOSApp iosApp = new IOSApp.fromPrebuiltApp('app.ipa');
+      final BufferLogger logger = context[Logger];
+      expect(logger.errorText, isEmpty);
+      expect(iosApp.bundleDir.path, endsWith('bundle.app'));
+      expect(iosApp.id, 'fooBundleId');
+      expect(iosApp.bundleName, 'bundle.app');
+    }, overrides: overrides);
+  });
 }
 
 const String _aaptData = '''
@@ -69,3 +191,23 @@
   'SWIFT_OPTIMIZATION_LEVEL': '-Onone',
   'SWIFT_VERSION': '3.0',
 };
+
+class MockIosWorkFlow extends Mock implements IOSWorkflow {
+  @override
+  String getPlistValueFromFile(String path, String key) {
+    final File file = fs.file(path);
+    if (!file.existsSync()) {
+      return null;
+    }
+    return json.decode(file.readAsStringSync())[key];
+  }
+}
+
+// Contains no bundle identifier.
+const String badPlistData = '''
+{}
+''';
+
+const String plistData = '''
+{"CFBundleIdentifier": "fooBundleId"}
+''';