feat: add flutterTest (#2)

Author: felangel

.github/workflows/main.yaml

@@ -14,4 +14,6 @@ on:
 
 jobs:
   build:
-    uses: VeryGoodOpenSource/very_good_workflows/.github/workflows/dart_package.yml@v1
+    uses: VeryGoodOpenSource/very_good_workflows/.github/workflows/flutter_package.yml@v1
+    with:
+      flutter_version: 2.10.3

.gitignore

@@ -7,4 +7,5 @@ build/
 pubspec.lock
 
 # Files related to tests
-coverage/
+coverage/
+.test_coverage.dart

README.md

@@ -13,6 +13,20 @@ Developed with 💙 by [Very Good Ventures][very_good_ventures_link] 🦄
 
 A test runner for Flutter and Dart created by Very Good Ventures.
 
+## Usage
+
+```dart
+import 'package:very_good_test_runner/very_good_test_runner.dart';
+
+void main() {
+  flutterTest(workingDirectory: 'path/to/project').listen((TestEvent event) {
+    // React to `TestEvent` instances.
+    // See https://github.com/dart-lang/test/blob/master/pkgs/test/doc/json_reporter.md#json-reporter-protocol
+    print(event);
+  });
+}
+```
+
 [ci_badge]: https://github.com/VeryGoodOpenSource/very_good_test_runner/workflows/very_good_test_runner/badge.svg
 [ci_link]: https://github.com/VeryGoodOpenSource/very_good_test_runner/actions
 [coverage_badge]: https://raw.githubusercontent.com/VeryGoodOpenSource/very_good_test_runner/main/coverage_badge.svg

analysis_options.yaml

@@ -1 +1 @@
-include: package:very_good_analysis/analysis_options.2.4.0.yaml
+include: package:very_good_analysis/analysis_options.2.4.0.yaml

coverage_badge.svg

@@ -0,0 +1,8 @@
+// ignore_for_file: avoid_print
+
+import 'package:very_good_test_runner/very_good_test_runner.dart';
+
+void main() {
+  // React to `TestEvent` instances.
+  flutterTest().listen(print);
+}

lib/example/main.dart

@@ -0,0 +1,91 @@
+import 'dart:async';
+import 'dart:convert';
+
+import 'package:universal_io/io.dart';
+import 'package:very_good_test_runner/very_good_test_runner.dart';
+
+/// Signature for `Process.start`.
+typedef StartProcess = Future<Process> Function(
+  String executable,
+  List<String> arguments, {
+  String? workingDirectory,
+  Map<String, String>? environment,
+  bool includeParentEnvironment,
+  bool runInShell,
+  ProcessStartMode mode,
+});
+
+/// Runs `flutter test` and returns a stream of [TestEvent]
+/// reported by the process.
+///
+/// ```dart
+/// void main() {
+///   // React to `TestEvent` instances.
+///   flutterTest().listen(print);
+/// }
+/// ```
+Stream<TestEvent> flutterTest({
+  List<String>? arguments,
+  String? workingDirectory,
+  Map<String, String>? environment,
+  bool runInShell = false,
+  StartProcess startProcess = Process.start,
+}) {
+  final controller = StreamController<TestEvent>();
+  late StreamSubscription testEventSubscription;
+  late StreamSubscription errorSubscription;
+  late Future<Process> processFuture;
+
+  Future<void> _onListen() async {
+    processFuture = startProcess(
+      'flutter',
+      ['test', ...?arguments, '--reporter=json'],
+      environment: environment,
+      workingDirectory: workingDirectory,
+      runInShell: runInShell,
+    );
+    final process = await processFuture;
+    final errors = process.stderr.map((e) => utf8.decode(e).trim());
+    final testEvents = process.stdout.mapToTestEvents();
+    errorSubscription = errors.listen(controller.addError);
+    testEventSubscription = testEvents.listen(
+      controller.add,
+      onError: controller.addError,
+      onDone: controller.close,
+    );
+  }
+
+  Future<void> _onCancel() async {
+    await controller.close();
+    (await processFuture).kill();
+    await errorSubscription.cancel();
+    await testEventSubscription.cancel();
+  }
+
+  controller
+    ..onListen = _onListen
+    ..onCancel = _onCancel;
+
+  return controller.stream;
+}
+
+extension on Stream<List<int>> {
+  Stream<TestEvent> mapToTestEvents() {
+    return map(utf8.decode)
+        .expand<String>((msg) sync* {
+          for (final value in msg.split('\n')) {
+            final trimmedValue = value.trim();
+            if (trimmedValue.isNotEmpty) yield trimmedValue;
+          }
+        })
+        .expand<Object?>((j) {
+          try {
+            return [json.decode(j)];
+          } on FormatException {
+            return [];
+          }
+        })
+        .cast<Map<Object?, Object?>>()
+        .map((json) => TestEvent.fromJson(Map<String, dynamic>.from(json)));
+  }
+}

lib/src/flutter_test_runner.dart

@@ -1,3 +1,5 @@
+/// A test runner for Flutter and Dart created by Very Good Ventures.
 library very_good_test_runner;
 
+export 'src/flutter_test_runner.dart' show flutterTest;
 export 'src/models/models.dart';

lib/very_good_test_runner.dart

@@ -8,6 +8,7 @@ environment:
 
 dependencies:
   json_annotation: ^4.4.0
+  universal_io: ^2.0.0
 
 dev_dependencies:
   build_runner: ^2.0.0