List Java Instru Test Information From JUnit Runner

base/test/android/javatests/src/org/chromium/base/test/TestListInstrumentationRunListener.java

Index: base/test/android/javatests/src/org/chromium/base/test/TestListInstrumentationRunListener.java
diff --git a/base/test/android/javatests/src/org/chromium/base/test/TestListInstrumentationRunListener.java b/base/test/android/javatests/src/org/chromium/base/test/TestListInstrumentationRunListener.java
new file mode 100644
index 0000000000000000000000000000000000000000..71fa4e0aaf7c29b249e4d0e71892a1238578efa3
--- /dev/null
+++ b/base/test/android/javatests/src/org/chromium/base/test/TestListInstrumentationRunListener.java
@@ -0,0 +1,150 @@
+// Copyright 2017 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.base.test;
+
+import android.support.test.internal.runner.listener.InstrumentationRunListener;
+
+import org.json.JSONArray;
+import org.json.JSONObject;
+import org.junit.runner.Description;
+import org.junit.runner.Result;
+
+import org.chromium.base.Log;
+
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.OutputStreamWriter;
+import java.io.Writer;
+import java.lang.annotation.Annotation;
+import java.lang.reflect.Method;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+
+/**
+ * A RunListener that list out all the test information into a json file.
+ */
+public class TestListInstrumentationRunListener extends InstrumentationRunListener {
+    private static final String TAG = "TestListRunListener";
+    private static final Set<String> SKIP_METHODS = new HashSet<>(
+            Arrays.asList(new String[] {"toString", "hashCode", "annotationType", "equals"}));
+
+    private final Map<Class<?>, JSONObject> mTestClassJsonMap = new HashMap<>();
+    private final String mOutputPath;
+
+    public TestListInstrumentationRunListener(String outputPath) {
+        super();
+        mOutputPath = outputPath;
+    }
+
+    /**
+     * Store the test method description to a Map at the beginning of a test run.
+     */
+    @Override
+    public void testStarted(Description desc) throws Exception {
+        if (mTestClassJsonMap.containsKey(desc.getTestClass())) {
+            ((JSONArray) mTestClassJsonMap.get(desc.getTestClass()).get("methods"))
+                .put(getTestMethodJSON(desc));
+        } else {
+            Class<?> testClass = desc.getTestClass();
+            mTestClassJsonMap.put(desc.getTestClass(), new JSONObject()
+                    .put("class", testClass.getName())
+                    .put("superclass", testClass.getSuperclass().getName())
+                    .put("annotations",
+                            getAnnotationJSON(Arrays.asList(testClass.getAnnotations())))
+                    .put("methods", new JSONArray().put(getTestMethodJSON(desc))));
+        }
+    }
+
+    /**
+     * Create a JSONArray with all the test class JSONObjects and save it to listed output path.
+     */
+    @Override
+    public void testRunFinished(Result result) throws IOException {
+        Writer writer = null;
+        File file = new File(mOutputPath);
+        try {
+            writer = new OutputStreamWriter(new FileOutputStream(file), "UTF-8");
+            JSONArray allTestClassesJSON = new JSONArray(mTestClassJsonMap.values());
+            writer.write(allTestClassesJSON.toString());
+        } catch (IOException e) {
+            Log.e(TAG, "failed to write json to file", e);
+            throw e;
+        } finally {
+            if (writer != null) {
+                try {
+                    writer.close();
+                } catch (IOException e) {
+                    // Intentionally ignore IOException when closing writer
+                }
+            }
+        }
+    }
+
+    /**
+     * Return a JSONOject that represent a Description of a method".
+     */
+    static JSONObject getTestMethodJSON(Description desc) throws Exception {
+        return new JSONObject()
+                .put("method", desc.getMethodName())
+                .put("annotations", getAnnotationJSON(desc.getAnnotations()));
+    }
+
+    /**
+     * Create a JSONObject that represent a collection of anntations.
+     *
+     * For example, for the following group of annotations for ExampleClass
+     * <code>
+     * @A
+     * @B(message = "hello", level = 3)
+     * public class ExampleClass() {}
+     * </code>
+     *
+     * This method would return a JSONObject as such:
+     * <code>
+     * {
+     *   "A": {},
+     *   "B": {
+     *     "message": "hello",
+     *     "level": "3"
+     *   }
+     * }
+     * </code>
+     *
+     * The method accomplish this by though through each annotation and reflectively call the
+     * annotation's method to get the element value, with exceptions to methods like "equals()"
+     * or "hashCode".
+     */
+    static JSONObject getAnnotationJSON(Collection<Annotation> annotations)
+            throws Exception {
+        JSONObject annotationsJsons = new JSONObject();
+        for (Annotation a : annotations) {
+            JSONObject elementJsonObject = new JSONObject();
+            for (Method method : a.annotationType().getMethods()) {
+                if (SKIP_METHODS.contains(method.getName())) {
+                    continue;
+                }
+                try {
+                    Object value = method.invoke(a);
+                    if (value == null) {
+                        elementJsonObject.put(method.getName(), null);
+                    } else {
+                        elementJsonObject.put(method.getName(),
+                                value.getClass().isArray()
+                                        ? new JSONArray(Arrays.asList((Object[]) value))
+                                        : value.toString());
+                    }
+                } catch (IllegalArgumentException e) {
+                }
+            }
+            annotationsJsons.put(a.annotationType().getSimpleName(), elementJsonObject);
+        }
+        return annotationsJsons;
+    }
+}