Add an Engine class for running groups of test suites.

test/engine_test.dart

+// Copyright (c) 2015, 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.
+
+import 'package:unittest/src/declarer.dart';
+import 'package:unittest/src/engine.dart';
+import 'package:unittest/src/state.dart';
+import 'package:unittest/src/suite.dart';
+import 'package:unittest/unittest.dart';
+
+void main() {
+  var declarer;
+  setUp(() => declarer = new Declarer());
+
+  test("runs each test in each suite in order", () {
+    var testsRun = 0;
+    for (var i = 0; i < 4; i++) {
+      declarer.test("test ${i + 1}", expectAsync(() {
+        expect(testsRun, equals(i));
+        testsRun++;
+      }, max: 1));
+    }
+
+    var engine = new Engine([
+      new Suite("suite 1", declarer.tests.take(2)),
+      new Suite("suite 2", declarer.tests.skip(2))
+    ]);
+
+    return engine.run().then((_) => expect(testsRun, equals(4)));
+  });
+
+  test("emits each test before it starts running and after the previous test "
+      "finished", () {
+    var testsRun = 0;
+    for (var i = 0; i < 3; i++) {
+      declarer.test("test ${i + 1}", expectAsync(() => testsRun++, max: 1));
+    }
+
+    var engine = new Engine([new Suite("suite", declarer.tests)]);
+    engine.onTestStarted.listen(expectAsync((liveTest) {
+      // [testsRun] should be one less than the test currently running.
+      expect(liveTest.test.name, equals("test ${testsRun + 1}"));
+
+      // [Engine.onTestStarted] is guaranteed to fire before the first
+      // [LiveTest.onStateChange].
+      expect(liveTest.onStateChange.first,
+          completion(equals(const State(Status.running, Result.success))));
+    }, count: 3, max: 3));
+
+    return engine.run();
+  });
+
+  test(".run() returns true if every test passes", () {
+    for (var i = 0; i < 2; i++) {
+      declarer.test("test ${i + 1}", () {});
+    }
+
+    var engine = new Engine([new Suite("suite", declarer.tests)]);
+    expect(engine.run(), completion(isTrue));
+  });
+
+  test(".run() returns false if any test fails", () {
+    for (var i = 0; i < 2; i++) {
+      declarer.test("test ${i + 1}", () {});
+    }
+    declarer.test("failure", () => throw new TestFailure("oh no"));
+
+    var engine = new Engine([new Suite("suite", declarer.tests)]);
+    expect(engine.run(), completion(isFalse));
+  });
+
+  test(".run() returns false if any test errors", () {
+    for (var i = 0; i < 2; i++) {
+      declarer.test("test ${i + 1}", () {});
+    }
+    declarer.test("failure", () => throw "oh no");
+
+    var engine = new Engine([new Suite("suite", declarer.tests)]);
+    expect(engine.run(), completion(isFalse));
+  });
+
+  test(".run() may not be called more than once", () {
+    var engine = new Engine([]);
+    expect(engine.run(), completes);
+    expect(() => engine.run(), throwsStateError);
+  });
+}