Add solo test and group (#881)

CHANGELOG.md

@@ -1,3 +1,9 @@
+## 0.12.42
+
+* Add support for `solo` test and group. When the argument is `true` only tests
+  and groups marked as solo will be run. It is still recommended that users
+  instead filter their tests by using the runner argument `-n`.
+
 ## 0.12.41
 
 * Add support for debugging VM tests.

lib/src/backend/declarer.dart

@@ -80,6 +80,12 @@ class Declarer {
   /// Whether [build] has been called for this declarer.
   bool _built = false;
 
+  /// The tests and/or groups that have been flagged as solo.
+  final _soloEntries = new Set<GroupEntry>();
+
+  /// Whether any tests and/or groups have been flagged as solo.
+  bool get _solo => _soloEntries.isNotEmpty;
+
   /// The current zone-scoped declarer.
   static Declarer get current => Zone.current[#test.declarer] as Declarer;
 
@@ -127,7 +133,8 @@ class Declarer {
       skip,
       Map<String, dynamic> onPlatform,
       tags,
-      int retry}) {
+      int retry,
+      bool solo = false}) {
     _checkNotBuilt("test");
 
     var newMetadata = new Metadata.parse(
@@ -164,6 +171,10 @@ class Declarer {
           // useful errors when calling `test()` and `group()` within a test.
           zoneValues: {#test.declarer: this});
     }, trace: _collectTraces ? new Trace.current(2) : null, guarded: false));
+
+    if (solo) {
+      _soloEntries.add(_entries.last);
+    }
   }
 
   /// Creates a group of tests.
@@ -173,7 +184,8 @@ class Declarer {
       skip,
       Map<String, dynamic> onPlatform,
       tags,
-      int retry}) {
+      int retry,
+      bool solo = false}) {
     _checkNotBuilt("group");
 
     var newMetadata = new Metadata.parse(
@@ -197,6 +209,10 @@ class Declarer {
       throw new ArgumentError("Groups may not be async.");
     });
     _entries.add(declarer.build());
+
+    if (solo || declarer._solo) {
+      _soloEntries.add(_entries.last);
+    }
   }
 
   /// Returns [name] prefixed with this declarer's group name.
@@ -240,7 +256,10 @@ class Declarer {
     _checkNotBuilt("build");
 
     _built = true;
-    return new Group(_name, _entries.toList(),
+    var entries = _entries.toList();
+    if (_solo) entries.removeWhere((entry) => !_soloEntries.contains(entry));
+
+    return new Group(_name, entries,
         metadata: _metadata,
         trace: _trace,
         setUpAll: _setUpAll,

lib/test.dart

@@ -132,21 +132,29 @@ Declarer get _declarer {
 ///
 /// If multiple platforms match, the annotations apply in order as through
 /// they were in nested groups.
+///
+/// If the `solo` flag is `true`, only tests and groups marked as
+/// "solo" will be be run. This only restricts tests *within this test
+/// suite*—tests in other suites will run as normal. We recommend that users
+/// avoid this flag if possible and instead use the test runner flag `-n` to
+/// filter tests by name.
 @isTest
 void test(description, body(),
     {String testOn,
     Timeout timeout,
     skip,
     tags,
     Map<String, dynamic> onPlatform,
-    int retry}) {
+    int retry,
+    @deprecated bool solo = false}) {
   _declarer.test(description.toString(), body,
       testOn: testOn,
       timeout: timeout,
       skip: skip,
       onPlatform: onPlatform,
       tags: tags,
-      retry: retry);
+      retry: retry,
+      solo: solo);
 
   // Force dart2js not to inline this function. We need it to be separate from
   // `main()` in JS stack traces in order to properly determine the line and
@@ -202,21 +210,29 @@ void test(description, body(),
 ///
 /// If multiple platforms match, the annotations apply in order as through
 /// they were in nested groups.
+///
+/// If the `solo` flag is `true`, only tests and groups marked as
+/// "solo" will be be run. This only restricts tests *within this test
+/// suite*—tests in other suites will run as normal. We recommend that users
+/// avoid this flag if possible, and instead use the test runner flag `-n` to
+/// filter tests by name.
 @isTestGroup
 void group(description, body(),
     {String testOn,
     Timeout timeout,
     skip,
     tags,
     Map<String, dynamic> onPlatform,
-    int retry}) {
+    int retry,
+    @deprecated bool solo = false}) {
   _declarer.group(description.toString(), body,
       testOn: testOn,
       timeout: timeout,
       skip: skip,
       tags: tags,
       onPlatform: onPlatform,
-      retry: retry);
+      retry: retry,
+      solo: solo);
 
   // Force dart2js not to inline this function. We need it to be separate from
   // `main()` in JS stack traces in order to properly determine the line and

pubspec.yaml

@@ -1,5 +1,5 @@
 name: test
-version: 0.12.41
+version: 0.12.42-dev
 author: Dart Team <[email protected]>
 description: A library for writing dart unit tests.
 homepage: https://github.com/dart-lang/test

test/runner/solo_test.dart

@@ -0,0 +1,64 @@
+// Copyright (c) 2018, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+@TestOn("vm")
+import 'package:test_descriptor/test_descriptor.dart' as d;
+
+import 'package:test/test.dart';
+
+import '../io.dart';
+
+void main() {
+  test("only runs the tests marked as solo", () async {
+    await d.file("test.dart", """
+          import 'dart:async';
+
+          import 'package:test/test.dart';
+
+          void main() {
+            test("passes", () {
+              expect(true, isTrue);
+            }, solo: true);
+            test("failed", () {
+              throw 'some error';
+            });
+          }
+          """).create();
+
+    var test = await runTest(["test.dart"]);
+    expect(test.stdout, emitsThrough(contains("+1: All tests passed!")));
+    await test.shouldExit(0);
+  });
+
+  test("only runs groups marked as solo", () async {
+    await d.file("test.dart", """
+          import 'dart:async';
+
+          import 'package:test/test.dart';
+
+          void main() {
+            group('solo', () {
+              test("first pass", () {
+                expect(true, isTrue);
+              });
+              test("second pass", () {
+                expect(true, isTrue);
+              });
+            }, solo: true);
+            group('no solo', () {
+              test("failure", () {
+                throw 'some error';
+              });
+              test("another failure", () {
+                throw 'some error';
+              });
+            });
+          }
+          """).create();
+
+    var test = await runTest(["test.dart"]);
+    expect(test.stdout, emitsThrough(contains("+2: All tests passed!")));
+    await test.shouldExit(0);
+  });
+}