Add navigation support in plugins

pkg/analyzer_plugin/test/utilities/navigation_test.dart

Index: pkg/analyzer_plugin/test/utilities/navigation_test.dart
diff --git a/pkg/analyzer_plugin/test/utilities/navigation_test.dart b/pkg/analyzer_plugin/test/utilities/navigation_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..91babacaa771db61552163bea075d1dcf810865d
--- /dev/null
+++ b/pkg/analyzer_plugin/test/utilities/navigation_test.dart
@@ -0,0 +1,86 @@
+// Copyright (c) 2017, 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:analyzer/src/dart/analysis/driver.dart';
+import 'package:analyzer_plugin/protocol/protocol.dart';
+import 'package:analyzer_plugin/utilities/navigation.dart';
+import 'package:test/test.dart';
+import 'package:test_reflective_loader/test_reflective_loader.dart';
+
+void main() {
+  defineReflectiveTests(NavigationGeneratorTest);
+}
+
+@reflectiveTest
+class NavigationGeneratorTest {
+  test_none() {
+    NavigationGenerator generator = new NavigationGenerator(null, []);
+    List<Notification> notifications =
+        generator.generateNavigationNotification('a.dart');
+    expect(notifications, hasLength(1));
+  }
+
+  test_normal() {
+    TestContributor contributor = new TestContributor();
+    NavigationGenerator generator =
+        new NavigationGenerator(null, [contributor]);
+    List<Notification> notifications =
+        generator.generateNavigationNotification('a.dart');
+    expect(notifications, hasLength(1));
+    expect(contributor.count, 1);
+  }
+
+  /**
+   * This tests that we get an error notification for each contributor that
+   * throws an error and that an error in one contributor doesn't prevent other
+   * contributors from being called.
+   */
+  test_withException() {
+    TestContributor contributor1 = new TestContributor();
+    TestContributor contributor2 = new TestContributor(throwException: true);
+    TestContributor contributor3 = new TestContributor();
+    TestContributor contributor4 = new TestContributor(throwException: true);
+    NavigationGenerator generator = new NavigationGenerator(
+        null, [contributor1, contributor2, contributor3, contributor4]);
+    List<Notification> notifications =
+        generator.generateNavigationNotification('a.dart');
+    expect(notifications, hasLength(3));
+    expect(
+        notifications.where(
+            (notification) => notification.event == 'analysis.navigation'),
+        hasLength(1));
+    expect(
+        notifications
+            .where((notification) => notification.event == 'plugin.error'),
+        hasLength(2));
+    expect(contributor1.count, 1);
+    expect(contributor2.count, 1);
+    expect(contributor3.count, 1);
+    expect(contributor4.count, 1);
+  }
+}
+
+class TestContributor implements NavigationContributor {
+  /**
+   * A flag indicating whether the contributor should throw an exception when
+   * [computeNavigation] is invoked.
+   */
+  bool throwException;
+
+  /**
+   * The number of times that [computeNavigation] was invoked.
+   */
+  int count = 0;
+
+  TestContributor({this.throwException: false});
+
+  @override
+  void computeNavigation(NavigationCollector collector,
+      AnalysisDriverGeneric driver, String filePath, int offset, int length) {
+    count++;
+    if (throwException) {
+      throw new Exception();
+    }
+  }
+}