📰 Add tests for Tile and TileGroup

testing/android/junit/java/src/org/chromium/testing/local/AnnotationProcessor.java

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.testing.local;
 
 import org.junit.rules.ExternalResource;
 import org.junit.runner.Description;
 import org.junit.runners.model.Statement;
 
@@ skipping 19 matching lines @@
  *    @Test
  *    @Foo
  *    public void myTest() { ... }
  * }
  * </pre>
  *
  * @param <T> type of the annotation to match on the test case.
  */
 public abstract class AnnotationProcessor<T extends Annotation> extends ExternalResource {
     private final Class<T> mAnnotationClass;
+    private final boolean mAlwaysApply;
     private Description mTestDescription;
     private T mAnnotation;
 
-    public AnnotationProcessor(Class<T> annotationClass) {
+    /**
+     * @param annotationClass The annotation to detect to trigger to rule.
+     * @param alwaysApply Whether the rule should trigger even when the annotation is not found.
+     */
+    public AnnotationProcessor(Class<T> annotationClass, boolean alwaysApply) {

[Bernhard Bauer, 2017/03/03 11:54:39]

I find it a bit strange to have AnnotationProcessor not always require an
annotation, but I can't think of a much better way off the top of my head
either.

[dgn, 2017/03/03 13:48:30]

Currently just adding @EnableFeatures at the class level would mean that the
rule would set a default value for all the tests. So I could remove the
alwaysApply argument. I just thought that adding @Rule should be already
indicating intent, and it feels redundant to still have to set a default. But if
you prefer I can do it that way.

         mAnnotationClass = annotationClass;
+        mAlwaysApply = alwaysApply;
     }
 
     @Override
     public Statement apply(Statement base, Description description) {
         mTestDescription = description;
         mAnnotation = description.getAnnotation(mAnnotationClass);

[Bernhard Bauer, 2017/03/03 11:54:38]

Maybe extract getting the annotation into a helper method, and then do 

  if (mAnnotation != null || mAlwaysApply) return supper.apply(base,
description);

[dgn, 2017/03/03 13:48:30]

Done.

-        if (mAnnotation == null) return base;
+        if (mAnnotation != null) return super.apply(base, description);
 
-        // Return the wrapped statement to execute before() and after().
-        return super.apply(base, description);
+        mAnnotation = description.getTestClass().getAnnotation(mAnnotationClass);
+        if (mAnnotation != null) return super.apply(base, description);
+
+        // No annotation, return the plain statement without executing before() and after().
+        return mAlwaysApply ? super.apply(base, description) : base;
     }
 
     /** @return {@link Description} of the current test. */
     protected Description getTestDescription() {
         return mTestDescription;
     }
 
     /** @return the annotation that caused the test to be processed. */
     protected T getAnnotation() {
         return mAnnotation;
     }
 }