[Conductor] Add ability to override mirror, add tests for default arg parsing and custom arg parsing (#154363)

fixes #154342

dev/conductor/core/lib/src/start.dart

@@ -60,6 +60,11 @@ class StartCommand extends Command<void> {
       help: 'The target release channel for the release.',
       allowed: kBaseReleaseChannels,
     );
+    argParser.addOption(
+      kFrameworkMirrorOption,
+      help:
+          'Configurable Framework repo mirror remote.',
+    );
     argParser.addOption(
       kFrameworkUpstreamOption,
       defaultsTo: FrameworkRepository.defaultUpstream,
@@ -112,14 +117,8 @@ class StartCommand extends Command<void> {
   @override
   String get description => 'Initialize a new Flutter release.';
 
-  @override
+  @visibleForTesting
-  Future<void> run() async {
+  StartContext createContext(ArgResults argumentResults) {
-    final ArgResults argumentResults = argResults!;
-    if (!platform.isMacOS && !platform.isLinux) {
-      throw ConductorException(
-        'Error! This tool is only supported on macOS and Linux',
-      );
-    }
 
     final String frameworkUpstream = getValueFromEnvOrArgs(
       kFrameworkUpstreamOption,
@@ -131,7 +130,12 @@ class StartCommand extends Command<void> {
       argumentResults,
       platform.environment,
     )!;
-    final String frameworkMirror =
+    final String frameworkMirror = getValueFromEnvOrArgs(
+          kFrameworkMirrorOption,
+          argumentResults,
+          platform.environment,
+          allowNull: true,
+        ) ??
         'git@github.com:$githubUsername/flutter.git';
     final String engineUpstream = getValueFromEnvOrArgs(
       kEngineUpstreamOption,
@@ -175,7 +179,7 @@ class StartCommand extends Command<void> {
       versionOverride = Version.fromString(versionOverrideString);
     }
 
-    final StartContext context = StartContext(
+    return StartContext(
       candidateBranch: candidateBranch,
       checkouts: checkouts,
       dartRevision: dartRevision,
@@ -191,7 +195,18 @@ class StartCommand extends Command<void> {
       versionOverride: versionOverride,
       githubUsername: githubUsername,
     );
-    return context.run();
+  }
+
+  @override
+  Future<void> run() async {
+    final ArgResults argumentResults = argResults!;
+    if (!platform.isMacOS && !platform.isLinux) {
+      throw ConductorException(
+        'Error! This tool is only supported on macOS and Linux',
+      );
+    }
+
+    return createContext(argumentResults).run();
   }
 }
 

dev/conductor/core/test/start_test.dart

@@ -23,8 +23,7 @@ void main() {
     const String flutterRoot = '/flutter';
     const String checkoutsParentDirectory = '$flutterRoot/dev/tools/';
     const String githubUsername = 'user';
-    const String frameworkMirror =
+    const String frameworkMirror = 'git@github.com:$githubUsername/flutter.git';
-        'git@github.com:$githubUsername/flutter.git';
     const String engineMirror = 'git@github.com:$githubUsername/engine.git';
     const String candidateBranch = 'flutter-1.2-candidate.3';
     const String releaseChannel = 'beta';
@@ -76,6 +75,85 @@ void main() {
       return CommandRunner<void>('codesign-test', '')..addCommand(command);
     }
 
+    group('start arg parser', () {
+      const String nextDartRevision =
+          'f6c91128be6b77aef8351e1e3a9d07c85bc2e46e';
+      late StartCommand startCommand;
+      setUp(() {
+        final String operatingSystem = const LocalPlatform().operatingSystem;
+        final Map<String, String> environment = <String, String>{
+          'HOME': '/path/to/user/home',
+        };
+        final Directory homeDir = fileSystem.directory(
+          environment['HOME'],
+        );
+        // Tool assumes this exists
+        homeDir.createSync(recursive: true);
+        platform = FakePlatform(
+          environment: environment,
+          operatingSystem: operatingSystem,
+          pathSeparator: '/',
+        );
+        processManager = FakeProcessManager.list(<FakeCommand>[]);
+        checkouts = Checkouts(
+          fileSystem: fileSystem,
+          parentDirectory: fileSystem.directory(checkoutsParentDirectory),
+          platform: platform,
+          processManager: processManager,
+          stdio: stdio,
+        );
+        startCommand = StartCommand(
+            checkouts: checkouts, conductorVersion: conductorVersion);
+      });
+
+      test('default args', () async {
+        final List<String> args = <String>[
+          'start',
+          '--$kCandidateOption',
+          candidateBranch,
+          '--$kReleaseOption',
+          'stable',
+          '--$kStateOption',
+          '/path/to/statefile.json',
+          '--$kDartRevisionOption',
+          nextDartRevision,
+          '--$kGithubUsernameOption',
+          githubUsername,
+        ];
+        final StartContext context =
+            startCommand.createContext(startCommand.argParser.parse(args));
+        expect(context.frameworkUpstream, FrameworkRepository.defaultUpstream);
+        expect(context.frameworkMirror, contains(githubUsername));
+        expect(context.frameworkMirror, contains('/flutter.git'));
+        expect(context.engineUpstream, EngineRepository.defaultUpstream);
+      });
+
+      test('overridden mirror', () async {
+        const String customFrameworkMirror =
+            'git@github.com:$githubUsername/flutter-work.git';
+        final List<String> args = <String>[
+          'start',
+          '--$kCandidateOption',
+          candidateBranch,
+          '--$kReleaseOption',
+          'stable',
+          '--$kStateOption',
+          '/path/to/statefile.json',
+          '--$kDartRevisionOption',
+          nextDartRevision,
+          '--$kGithubUsernameOption',
+          githubUsername,
+          '--$kFrameworkMirrorOption',
+          customFrameworkMirror,
+        ];
+        final StartContext context =
+            startCommand.createContext(startCommand.argParser.parse(args));
+        expect(
+          context.frameworkMirror, customFrameworkMirror
+        );
+      });
+    });
+
     test('throws exception if run from Windows', () async {
       final CommandRunner<void> runner = createRunner(
         commands: <FakeCommand>[