Add utility method to SubscriptionManager

pkg/analyzer_plugin/test/utilities/subscriptions/subscription_manager_test.dart

Index: pkg/analyzer_plugin/test/utilities/subscriptions/subscription_manager_test.dart
diff --git a/pkg/analyzer_plugin/test/utilities/subscriptions/subscription_manager_test.dart b/pkg/analyzer_plugin/test/utilities/subscriptions/subscription_manager_test.dart
index 4bf79ff8283d036a1fee04db8cde11fd4dc4dfd3..49cdae338d9b63c6210439c648a66322ccc3aec0 100644
--- a/pkg/analyzer_plugin/test/utilities/subscriptions/subscription_manager_test.dart
+++ b/pkg/analyzer_plugin/test/utilities/subscriptions/subscription_manager_test.dart
@@ -15,14 +15,36 @@ void main() {
 class SubscriptionManagerTest {
   SubscriptionManager manager = new SubscriptionManager();
 
+  String fooPath = '/project/lib/foo.dart';
+  String barPath = '/project/lib/bar.dart';
+  String bazPath = '/project/lib/baz.dart';
+
+  test_hasSubscriptionForFile_differentSubscription() {
+    manager.setSubscriptions({
+      AnalysisService.NAVIGATION: [barPath]
+    });
+    expect(manager.hasSubscriptionForFile(fooPath, AnalysisService.HIGHLIGHTS),
+        isFalse);
+  }
+
+  test_hasSubscriptionForFile_hasSubscription() {
+    manager.setSubscriptions({
+      AnalysisService.HIGHLIGHTS: [fooPath]
+    });
+    expect(manager.hasSubscriptionForFile(fooPath, AnalysisService.HIGHLIGHTS),
+        isTrue);
+  }
+
+  test_hasSubscriptionForFile_noSubscription() {
+    expect(manager.hasSubscriptionForFile(fooPath, AnalysisService.HIGHLIGHTS),
+        isFalse);
+  }
+
   test_servicesForFile() {
     expect(manager.servicesForFile('/project/lib/test.dart'), hasLength(0));
   }
 
   test_setSubscriptions() {
-    String fooPath = '/project/lib/foo.dart';
-    String barPath = '/project/lib/bar.dart';
-    String bazPath = '/project/lib/baz.dart';
     //
     // Set the initial set of subscriptions.
     //