Android Service Test——ServiceTestCase

云少嘎嘎嘎

      在网上搜了半天，发现关于ServiceTestCase的文章少得可怜，而在SDK中也只有少量的说明，还是自己总结研究一下吧，以下内容大部分出自SDK，外加自己的理解，可能会有理解错误的地方。
      根据SDK中的说明画了一个类的继承图如下：

       从图中可以看出ServiceTestCase继承了JUnit的TestCase类，因此可以可以在测试中控制程序和服务进行测试工作。另外还可以提供mock application和Context将服务独立系统，这点非常重要，应该可以消除服务对外部的依赖，但还需要进行进一步的研究才能确定。

       对于ServiceTestCase有一下几点需要注意：

       1.ServiceTestCase.startService()和ServiceTestCase.bindService()这两个方法负责完成测试环境的初始化工作，其中包括mock objects，然后启动服务。

       2.ServiceTestCase.bindService()和Service.bindService()方法的不同之处在于其返回值的类型：
                ServiceTestCase.bindService()——>Intent
                Service.bindService()——>IBinder object

      3.同其余的测试一样，ServiceTestCase也在每次测试的时候调用setUp()方法，该方法会通过复制当前的系统Context来建立测试平台，通过调用getSystemContext()方法可以获得此Context。如果要重写这个方法，则第一句必须为super.setUp()。

     4.setApplication()和setContext(Context)可以在启动服务前设定mock Context和mock Application。

     5.在运行前，ServiceTestCase会默认地运行testAndroidTestCaseSetupProperly()方法来确定测试类正确地搭建好了Context

     那么对于Service进行测试到底要测什么呢？在SDK中所提到的主要有以下几个方面：
    
     1.调用Context.startService()或者Context.bindService()后要确定onCreate()方法被正确地调用；同样，当调用Context.stopService(), Context.unbindService(), stopSelf()或者 stopSelfResult()等方法时要确定onDestroy()方法被正确地调用。
 
     2.服务能够正确地处理Context.startService()的多次调用，只有第一次调用才会触发Service.onCreate()方法，但是每次都会调用Service.onStartCommand()方法。还要注意的是startService()不会嵌套调用，因此对Context.stopService()或者 Service.stopSelf() ( stopSelf(int)不再此列)的一次调用就应该能够终止服务。

     3.测试服务在实现上的逻辑正确性。

      以上都是些理论上的东西，下篇文章结合例子从头完成对一个服务的测试。下面附上ServiceTestCase类的源代码，以供参考。

      

1. /**
   
2.  * Copyright (C) 2008 The Android Open Source Project
   
3.  *
   
4.  * Licensed under the Apache License, Version 2.0 (the "License");
   
5.  * you may not use this file except in compliance with the License.
   
6.  * You may obtain a copy of the License at
   
7.  *
   
8.  * http://www.apache.org/licenses/LICENSE-2.0
   
9.  *
   
10.  * Unless required by applicable law or agreed to in writing, software
    
11.  * distributed under the License is distributed on an "AS IS" BASIS,
    
12.  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    
13.  * See the License for the specific language governing permissions and
    
14.  * limitations under the License.
    
15.  */
    
16. 
    
17. package android.test;
    
18. 
    
19. import android.app.Application;
    
20. import android.app.Service;
    
21. import android.content.ComponentName;
    
22. import android.content.Context;
    
23. import android.content.Intent;
    
24. import android.os.IBinder;
    
25. import android.os.RemoteException;
    
26. import android.test.mock.MockApplication;
    
27. 
    
28. import java.lang.reflect.Field;
    
29. import java.util.Random;
    
30. 
    
31. /***
    
32.  * This test case provides a framework in which you can test Service classes in
    
33.  * a controlled environment. It provides basic support for the lifecycle of a
    
34.  * Service, and hooks by which you can inject various dependencies and control
    
35.  * the environment in which your Service is tested.
    
36.  *
    
37.  * <p><b>Lifecycle Support.</b>
    
38.  * Every Service is designed to be accessed within a specific sequence of
    
39.  * calls. <insert link to Service lifecycle doc here>.
    
40.  * In order to support the lifecycle of a Service, this test case will make the
    
41.  * following calls at the following times.
    
42.  *
    
43.  * <ul>
44. The test case will not call onCreate() until your test calls
    
45.  * {@link #startService} or {@link #bindService}. This gives you a chance
    
46.  * to set up or adjust any additional framework or test logic before
    
47.  * onCreate().


48.  *
49. When your test calls {@link #startService} or {@link #bindService}
    
50.  * the test case will call onCreate(), and then call the corresponding entry point in your service.
    
51.  * It will record any parameters or other support values necessary to support the lifecycle.


52.  *
53. After your test completes, the test case {@link #tearDown} function is
    
54.  * automatically called, and it will stop and destroy your service with the appropriate
    
55.  * calls (depending on how your test invoked the service.)


56.  * </ul>
    
57.  *
    
58.  * <p><b>Dependency Injection.</b>
    
59.  * Every service has two inherent dependencies, the {@link android.content.Context Context} in
    
60.  * which it runs, and the {@link android.app.Application Application} with which it is associated.
    
61.  * This framework allows you to inject modified, mock, or isolated replacements for these
    
62.  * dependencies, and thus perform a true unit test.
    
63.  *
    
64.  * <p>If simply run your tests as-is, your Service will be injected with a fully-functional
    
65.  * Context, and a generic {@link android.test.mock.MockApplication MockApplication} object.
    
66.  * You can create and inject alternatives to either of these by calling
    
67.  * {@link AndroidTestCase#setContext(Context) setContext()} or
    
68.  * {@link #setApplication setApplication()}. You must do this <i>before</i> calling
    
69.  * startService() or bindService(). The test framework provides a
    
70.  * number of alternatives for Context, including {link android.test.mock.MockContext MockContext},
    
71.  * {@link android.test.RenamingDelegatingContext RenamingDelegatingContext}, and
    
72.  * {@link android.content.ContextWrapper ContextWrapper}.
    
73.  */
    
74. public abstract class ServiceTestCase<T extends Service> extends AndroidTestCase {
    
75. 
    
76.     Class<T> mServiceClass;
    
77. 
    
78.     private Context mSystemContext;
    
79.     private Application mApplication;
    
80. 
    
81.     public ServiceTestCase(Class<T> serviceClass) {
    
82.         mServiceClass = serviceClass;
    
83.     }
    
84. 
    
85.     private T mService;
    
86.     private boolean mServiceAttached = false;
    
87.     private boolean mServiceCreated = false;
    
88.     private boolean mServiceStarted = false;
    
89.     private boolean mServiceBound = false;
    
90.     private Intent mServiceIntent = null;
    
91.     private int mServiceId;
    
92. 
    
93.     /***
    
94.      * @return Returns the actual service under test.
    
95.      */
    
96.     public T getService() {
    
97.         return mService;
    
98.     }
    
99. 
    
100.     /***
     
101.      * This will do the work to instantiate the Service under test. After this, your test
     
102.      * code must also start and stop the service.
     
103.      */
     
104.     @Override
     
105.     protected void setUp() throws Exception {
     
106.         super.setUp();
     
107.         
     
108.         // get the real context, before the individual tests have a chance to muck with it
     
109.         mSystemContext = getContext();
     
110. 
     
111.     }
     
112.     
     
113.     /***
     
114.      * Create the service under test and attach all injected dependencies (Context, Application) to
     
115.      * it. This will be called automatically by {@link #startService} or by {@link #bindService}.
     
116.      * If you wish to call {@link AndroidTestCase#setContext(Context) setContext()} or
     
117.      * {@link #setApplication setApplication()}, you must do so before calling this function.
     
118.      */
     
119.     protected void setupService() {
     
120.         mService = null;
     
121.         try {
     
122.             mService = mServiceClass.newInstance();
     
123.         } catch (Exception e) {
     
124.             assertNotNull(mService);
     
125.         }
     
126.         if (getApplication() == null) {
     
127.             setApplication(new MockApplication());
     
128.         }
     
129.         mService.attach(
     
130.                 getContext(),
     
131.                 null, // ActivityThread not actually used in Service
     
132.                 mServiceClass.getName(),
     
133.                 null, // token not needed when not talking with the activity manager
     
134.                 getApplication(),
     
135.                 null // mocked services don't talk with the activity manager
     
136.                 );
     
137.         
     
138.         assertNotNull(mService);
     
139.         
     
140.         mServiceId = new Random().nextInt();
     
141.         mServiceAttached = true;
     
142.     }
     
143.     
     
144.     /***
     
145.      * Start the service under test, in the same way as if it was started by
     
146.      * {@link android.content.Context#startService Context.startService()}, providing the
     
147.      * arguments it supplied. If you use this method to start the service, it will automatically
     
148.      * be stopped by {@link #tearDown}.
     
149.      *
     
150.      * @param intent The Intent as if supplied to {@link android.content.Context#startService}.
     
151.      */
     
152.     protected void startService(Intent intent) {
     
153.         assertFalse(mServiceStarted);
     
154.         assertFalse(mServiceBound);
     
155.         
     
156.         if (!mServiceAttached) {
     
157.             setupService();
     
158.         }
     
159.         assertNotNull(mService);
     
160.         
     
161.         if (!mServiceCreated) {
     
162.             mService.onCreate();
     
163.             mServiceCreated = true;
     
164.         }
     
165.         mService.onStart(intent, mServiceId);
     
166.         
     
167.         mServiceStarted = true;
     
168.     }
     
169.     
     
170.     /***
     
171.      * Start the service under test, in the same way as if it was started by
     
172.      * {@link android.content.Context#bindService Context.bindService()}, providing the
     
173.      * arguments it supplied.
     
174.      *
     
175.      * Return the communication channel to the service. May return null if
     
176.      * clients can not bind to the service. The returned
     
177.      * {@link android.os.IBinder} is usually for a complex interface
     
178.      * that has been <a href="{@docRoot}guide/developing/tools/aidl.html">described using
     
179.      * aidl.
     
180.      *
     
181.      * Note: In order to test with this interface, your service must implement a getService()
     
182.      * method, as shown in samples.ApiDemos.app.LocalService.
     
183. 
     
184.      * @param intent The Intent as if supplied to {@link android.content.Context#bindService}.
     
185.      *
     
186.      * @return Return an IBinder for making further calls into the Service.
     
187.      */
     
188.     protected IBinder bindService(Intent intent) {
     
189.         assertFalse(mServiceStarted);
     
190.         assertFalse(mServiceBound);
     
191.         
     
192.         if (!mServiceAttached) {
     
193.             setupService();
     
194.         }
     
195.         assertNotNull(mService);
     
196.         
     
197.         if (!mServiceCreated) {
     
198.             mService.onCreate();
     
199.             mServiceCreated = true;
     
200.         }
     
201.         // no extras are expected by unbind
     
202.         mServiceIntent = intent.cloneFilter();
     
203.         IBinder result = mService.onBind(intent);
     
204.         
     
205.         mServiceBound = true;
     
206.         return result;
     
207.     }
     
208.     
     
209.     /***
     
210.      * This will make the necessary calls to stop (or unbind) the Service under test, and
     
211.      * call onDestroy(). Ordinarily this will be called automatically (by {@link #tearDown}, but
     
212.      * you can call it directly from your test in order to check for proper shutdown behaviors.
     
213.      */
     
214.     protected void shutdownService() {
     
215.         if (mServiceStarted) {
     
216.             mService.stopSelf();
     
217.             mServiceStarted = false;
     
218.         } else if (mServiceBound) {
     
219.             mService.onUnbind(mServiceIntent);
     
220.             mServiceBound = false;
     
221.         }
     
222.         if (mServiceCreated) {
     
223.             mService.onDestroy();
     
224.         }
     
225.     }
     
226.     
     
227.     /***
     
228.      * Shuts down the Service under test. Also makes sure all resources are cleaned up and
     
229.      * garbage collected before moving on to the next
     
230.      * test. Subclasses that override this method should make sure they call super.tearDown()
     
231.      * at the end of the overriding method.
     
232.      *
     
233.      * @throws Exception
     
234.      */
     
235.     @Override
     
236.     protected void tearDown() throws Exception {
     
237.         shutdownService();
     
238.         mService = null;
     
239. 
     
240.         // Scrub out members - protects against memory leaks in the case where someone
     
241.         // creates a non-static inner class (thus referencing the test case) and gives it to
     
242.         // someone else to hold onto
     
243.         scrubClass(ServiceTestCase.class);
     
244. 
     
245.         super.tearDown();
     
246.     }
     
247.     
     
248.     /***
     
249.      * Set the application for use during the test. If your test does not call this function,
     
250.      * a new {@link android.test.mock.MockApplication MockApplication} object will be generated.
     
251.      *
     
252.      * @param application The Application object that will be injected into the Service under test.
     
253.      */
     
254.     public void setApplication(Application application) {
     
255.         mApplication = application;
     
256.     }
     
257. 
     
258.     /***
     
259.      * Return the Application object being used by the Service under test.
     
260.      *
     
261.      * @return Returns the application object.
     
262.      *
     
263.      * @see #setApplication
     
264.      */
     
265.     public Application getApplication() {
     
266.         return mApplication;
     
267.     }
     
268.     
     
269.     /***
     
270.      * Return a real (not mocked or instrumented) system Context that can be used when generating
     
271.      * Mock or other Context objects for your Service under test.
     
272.      *
     
273.      * @return Returns a reference to a normal Context.
     
274.      */
     
275.     public Context getSystemContext() {
     
276.         return mSystemContext;
     
277.     }
     
278. 
     
279.     public void testServiceTestCaseSetUpProperly() throws Exception {
     
280.         setupService();
     
281.         assertNotNull("service should be launched successfully", mService);
     
282.     }
     
283. }