docs/html/tools/testing/service_testing.jd

page.title=Service Testing
parent.title=Testing
parent.link=index.html
@jd:body

<div id="qv-wrapper">
  <div id="qv">
  <h2>In this document</h2>
  <ol>
    <li>
        <a href="#DesignAndTest">Service Design and Testing</a>
    </li>
    <li>
        <a href="#ServiceTestCase">ServiceTestCase</a>
    </li>
    <li>
        <a href="#MockObjects">Mock object classes</a>
    </li>
    <li>
        <a href="#TestAreas">What to Test</a>
    </li>
  </ol>
  <h2>Key Classes</h2>
    <ol>
      <li>{@link android.test.InstrumentationTestRunner}</li>
      <li>{@link android.test.ServiceTestCase}</li>
      <li>{@link android.test.mock.MockApplication}</li>
      <li>{@link android.test.RenamingDelegatingContext}</li>
    </ol>
  <h2>Related Tutorials</h2>
    <ol>
        <li>
            <a href="{@docRoot}tools/testing/activity_test.html">Activity Testing Tutorial</a>
        </li>
    </ol>
  <h2>See Also</h2>
      <ol>
        <li>
          <a href="{@docRoot}tools/testing/testing_eclipse.html">
          Testing From Eclipse with ADT</a>
        </li>
        <li>
          <a href="{@docRoot}tools/testing/testing_otheride.html">
          Testing From Other IDEs</a>
        </li>
      </ol>
  </div>
</div>
<p>
    Android provides a testing framework for Service objects that can run them in
    isolation and provides mock objects. The test case class for Service objects is
    {@link android.test.ServiceTestCase}. Since the Service class assumes that it is separate
    from its clients, you can test a Service object without using instrumentation.
</p>
<p>
    This document describes techniques for testing Service objects. If you aren't familiar with the
    Service class, please read the <a href="{@docRoot}guide/components/services.html">
    Services</a> document. If you aren't familiar with Android testing, please read
    <a href="{@docRoot}tools/testing/testing_android.html">Testing Fundamentals</a>,
    the introduction to the Android testing and instrumentation framework.
</p>
<h2 id="DesignAndTest">Service Design and Testing</h2>
<p>
    When you design a Service, you should consider how your tests can examine the various states
    of the Service lifecycle. If the lifecycle methods that start up your Service, such as
    {@link android.app.Service#onCreate() onCreate()} or
    {@link android.app.Service#onStartCommand(Intent, int, int) onStartCommand()} do not normally
    set a global variable to indicate that they were successful, you may want to provide such a
    variable for testing purposes.
</p>
<p>
    Most other testing is facilitated by the methods in the {@link android.test.ServiceTestCase}
    test case class. For example, the {@link android.test.ServiceTestCase#getService()} method
    returns a handle to the Service under test, which you can test to confirm that the Service is
    running even at the end of your tests.
</p>
<h2 id="ServiceTestCase">ServiceTestCase</h2>
<p>
    {@link android.test.ServiceTestCase} extends the JUnit {@link junit.framework.TestCase} class
    with with methods for testing application permissions and for controlling the application and
    Service under test. It also provides mock application and Context objects that isolate your
    test from the rest of the system.
</p>
<p>
    {@link android.test.ServiceTestCase} defers initialization of the test environment until you
    call {@link android.test.ServiceTestCase#startService(Intent) ServiceTestCase.startService()} or
    {@link android.test.ServiceTestCase#bindService(Intent) ServiceTestCase.bindService()}. This
    allows you to set up your test environment, particularly your mock objects, before the Service
    is started.
</p>
<p>
    Notice that the parameters to <code>ServiceTestCase.bindService()</code>are different from
    those for <code>Service.bindService()</code>. For the <code>ServiceTestCase</code> version,
    you only provide an Intent. Instead of returning a boolean,
    <code>ServiceTestCase.bindService()</code> returns an object that subclasses
    {@link android.os.IBinder}.
</p>
<p>
    The {@link android.test.ServiceTestCase#setUp()} method for {@link android.test.ServiceTestCase}
    is called before each test. It sets up the test fixture by making a copy of the current system
    Context before any test methods touch it. You can retrieve this Context by calling
    {@link android.test.ServiceTestCase#getSystemContext()}. If you override this method, you must
    call <code>super.setUp()</code> as the first statement in the override.
</p>
<p>
    The methods {@link android.test.ServiceTestCase#setApplication(Application) setApplication()}
    and {@link android.test.AndroidTestCase#setContext(Context)} setContext()} allow you to set
    a mock Context or mock Application (or both) for the Service, before you start it. These mock
    objects are described in <a href="#MockObjects">Mock object classes</a>.
</p>
<p>
    By default, {@link android.test.ServiceTestCase} runs the test method
    {@link android.test.AndroidTestCase#testAndroidTestCaseSetupProperly()}, which asserts that
    the base test case class successfully set up a Context before running.
</p>
<h2 id="MockObjects">Mock object classes</h2>
<p>
    <code>ServiceTestCase</code> assumes that you will use a mock Context or mock Application
    (or both) for the test environment. These objects isolate the test environment from the
    rest of the system. If you don't provide your own instances of these objects before you
    start the Service, then {@link android.test.ServiceTestCase} will create its own internal
    instances and inject them into the Service. You can override this behavior by creating and
    injecting your own instances before starting the Service
</p>
<p>
    To inject a mock Application object into the Service under test, first create a subclass of
    {@link android.test.mock.MockApplication}. <code>MockApplication</code> is a subclass of
    {@link android.app.Application} in which all the methods throw an Exception, so to use it
    effectively you subclass it and override the methods you need. You then inject it into the
    Service with the
    {@link android.test.ServiceTestCase#setApplication(Application) setApplication()} method.
    This mock object allows you to control the application values that the Service sees, and
    isolates it from the real system. In addition, any hidden dependencies your Service has on
    its application reveal themselves as exceptions when you run the test.
</p>
<p>
    You inject a mock Context into the Service under test with the
    {@link android.test.AndroidTestCase#setContext(Context) setContext()} method. The mock
    Context classes you can use are described in more detail in
    <a href="{@docRoot}tools/testing/testing_android.html#MockObjectClasses">
    Testing Fundamentals</a>.
</p>
<h2 id="TestAreas">What to Test</h2>
<p>
    The topic <a href="{@docRoot}tools/testing/what_to_test.html">What To Test</a>
    lists general considerations for testing Android components.
    Here are some specific guidelines for testing a Service:
</p>
<ul>
    <li>
        Ensure that the {@link android.app.Service#onCreate()} is called in response to
        {@link android.content.Context#startService(Intent) Context.startService()} or
    {@link android.content.Context#bindService(Intent,ServiceConnection,int) Context.bindService()}.
        Similarly, you should ensure that {@link android.app.Service#onDestroy()} is called in
        response to {@link android.content.Context#stopService(Intent) Context.stopService()},
        {@link android.content.Context#unbindService(ServiceConnection) Context.unbindService()},
        {@link android.app.Service#stopSelf()}, or
        {@link android.app.Service#stopSelfResult(int) stopSelfResult()}.
    </li>
    <li>
        Test that your Service correctly handles multiple calls from
        <code>Context.startService()</code>. Only the first call triggers
        <code>Service.onCreate()</code>, but all calls trigger a call to
        <code>Service.onStartCommand()</code>.
        <p>
            In addition, remember that <code>startService()</code> calls don't
            nest, so a single call to <code>Context.stopService()</code> or
            <code>Service.stopSelf()</code> (but not <code>stopSelf(int)</code>)
            will stop the Service. You should test that your Service stops at the correct point.
        </p>
    </li>
    <li>
        Test any business logic that your Service implements. Business logic includes checking for
        invalid values, financial and arithmetic calculations, and so forth.
    </li>
</ul>