tutorials/testing/helloandroid_test.jd

page.title=Hello, Testing
@jd:body
 <div id="qv-wrapper">
  <div id="qv">
  <h2>In this document</h2>
  <ol>
    <li>
        <a href="#CreateTestProject">Creating the Test Project</a>
    </li>
    <li>
        <a href="#CreateTestClass">Creating the Test Case Class</a>
        <ol>
            <li>
                <a href="#CreateTestCaseClassFile">Adding the test case class file</a>
            </li>
            <li>
                <a href="#CreateConstructor">Adding the test case constructor</a>
            </li>
            <li>
                <a href="#CreateSetUp">Adding a setup method</a>
            </li>
            <li>
                <a href="#CreatePreConditions">Adding a preconditions test</a>
            </li>
            <li>
                <a href="#CreateText">Adding a unit test</a>
            </li>
            <li>
                <a href="#CompleteTest">The finished test case class</a>
            </li>
        </ol>
    </li>
    <li>
        <a href="#RunTest">Running the Tests and Seeing the Results</a>
    </li>
    <li>
        <a href="#NextSteps">Next Steps</a>
    </li>
  </ol>
<h2>Related Tutorials</h2>
<ol>
    <li>
        <a href="{@docRoot}resources/tutorials/hello-world.html">Hello, World</a>
    </li>
    <li>
        <a href="{@docRoot}resources/tutorials/testing/activity_test.html">Activity Testing</a>
    </li>
</ol>
<h2>See Also</h2>
<ol>
    <li>
        <a href="{@docRoot}guide/topics/testing/testing_android.html">Testing Android Applications</a>
    </li>
    <li>
        {@link android.test.ActivityInstrumentationTestCase2}
    </li>
    <li>
        {@link android.test.InstrumentationTestRunner}
    </li>
</ol>

</div>
</div>
<p>
    Android offers a powerful but easy-to-use testing framework that is well integrated with the SDK tools. Because writing
    tests is an important part of any development effort, this tutorial introduces the basics of testing and helps you get started testing quickly.

    To keep things simple, this tutorial builds on the <a href="{@docRoot}resources/tutorials/hello-world.html">Hello World</a> tutorial, which you may have already completed.
    It guides you through the process of setting up a test project, adding a test, and running the test against the Hello World application, all from inside the Eclipse environment.
    Of course, when you are done with this tutorial, you will want to create a test project for your own app and add various types of tests to it.
</p>
<p>
    If you'd like to read an overview of the test and instrumentation framework and the core test case classes available, look at
    the <a href="{@docRoot}guide/topics/testing/testing_android.html">Testing Android Applications</a> topic.
    If you prefer a more advanced testing tutorial, try the
    <a href="{@docRoot}resources/tutorials/testing/activity_test.html">Activity Testing</a> tutorial.
</p>
<h2 id="Prerequisites">Prerequisites</h2>
    <p>
        This tutorial and its code depend on the Hello World tutorial. If you haven't completed that tutorial already,
        do so now. You will learn the fundamentals of Android application development, and you will
        have an Android application that is ready to be tested. The tutorial guides you through the
        setup of an Android test project using the ADT Plugin for Eclipse and other SDK tools.
        You will need an SDK development platform that is version 1.5
        (API level 3) or higher.
    </p>
    <p>
        If you aren't developing in Eclipse with ADT or you would like to run tests directly from the
        command line, please see the topic <a href="{@docRoot}guide/developing/testing/testing_otheride.html">Testing in Other IDEs</a>
        for instructions.
    </p>
<h2 id="CreateTestProject">Creating the Test Project</h2>
<p>
    In the Hello World tutorial you created Android application project called
    HelloAndroid. A test of an Android application is also an Android
    application, and you create it within an Eclipse project. The Eclipse with ADT
    <strong>New Android Test Project</strong> dialog creates a new test project and the
    framework of a new test application at the same time.
</p>
<p>
    To create the test project and test application framework in Eclipse with ADT, follow these steps
</p>
    <ol>
        <li>
            In Eclipse, select <strong>New</strong> &gt; <strong>Project</strong> &gt; <strong>Android</strong> &gt; <strong>Android Test Project</strong>.
            <p>
              <a href="{@docRoot}images/testing/hwtest_new_test_project_menu.png">
                  <img alt="New Android Test Project menu" src="{@docRoot}images/testing/hwtest_new_test_project_menu.png" style="height:230px"/>
              </a>
            </p>
            <p>
              The New Android Test Project dialog appears.
            </p>
        </li>
        <li>
            Set the following values:
            <ul>
                <li>
                    <em>Test Project Name:</em> &quot;HelloAndroidTest&quot;
                </li>
                <li>
                    <em>Test Target:</em> Set &quot;An existing Android project&quot;, click Browse, and then
                    select &quot;HelloAndroid&quot; from the list of projects.
                </li>
                <li>
                    <em>Build Target:</em> Set a target whose platform is Android 1.5 or above.
                </li>
                <li>
                    <em>Application name:</em> &quot;HelloAndroidTest&quot;
                </li>
                <li>
                    <em>Package name:</em> &quot;<code>com.example.helloandroid.test</code>&quot;
                </li>
            </ul>
            <p>
                The dialog should now look like this:
            </p>
            <a href="{@docRoot}images/testing/hwtest_new_test_project_dialog_complete_callouts.png">
                <img alt="New Android Test Project dialog with entries" src="{@docRoot}images/testing/hwtest_new_test_project_dialog_complete_callouts.png" style="height:230px"/>
            </a>
        </li>
        <li>
            Click Finish. The new project appears in the Package Explorer.
        </li>
    </ol>
<h2 id="CreateTestClass">Creating the Test Case Class</h2>
<p>
    You now have a test project HelloAndroidTest, and the basic structure of a test application
    also called HelloAndroidTest. The basic structure includes all the files and directories you
    need to build and run a test application, <em>except for</em> the class that contains
    your tests (the <strong>test case class</strong>).
</p>
<p>
    The next step is to define the test case class. In this tutorial, you define a test case class
    that extends one of Android's test case classes designed for Activities. The class contains
    definitions for four methods:
</p>
    <ol>
        <li>
            <code>HelloAndroidTest</code>: This defines the constructor for the class. It is
            required by the Android testing framework.
        </li>
        <li>
            <code>setUp()</code>: This overrides the JUnit <code>setUp()</code> method. You use
            it to initialize the environment before each test runs.
        </li>
        <li>
            <code>testPreconditions()</code>: This defines a small test that ensures the Hello, Android
            application starts up correctly.
        </li>
        <li>
            <code>testText()</code>: This tests that what is displayed on the screen is the
            same as what is contained in the application's string resources. It is an example of
            a real unit test you would perform against an application's UI.
        </li>
    </ol>
<p>
    The following sections contain the code for the test case class and its methods.
</p>

<h3 id="CreateTestCaseClassFile">Adding the test case class file</h3>
<p>
  To add the Java file for the test case class, follow these steps
</p>
    <ol>
        <li>
            In Eclipse, open the HelloAndroidTest project if it is not already open.
        </li>
        <li>
            Within HelloAndroidTest, expand the <code>src/</code> folder and
            then find the package icon for <code>com.example.helloandroid.test</code>.
            Right-click on the package icon and select <strong>New</strong> &gt; <strong>Class</strong>:
            <p>
              <a href="{@docRoot}images/testing/hwtest_create_test_class_menu_callouts.png">
                  <img alt="Menu for creating a new class in the test application" src="{@docRoot}images/testing/hwtest_create_test_class_menu_callouts.png" style="height:230px"/>
              </a>
            </p>
            <p>
                The New Java Class dialog appears.
            </p>
        </li>
        <li>
            In the dialog, enter the following:
            <ul>
                <li>
                    <em>Name:</em> &quot;HelloAndroidTest&quot;. This becomes the name of your test class.
                </li>
                <li>
                    <em>Superclass:</em> &quot;<code>android.test.ActivityInstrumentationTestCase2&lt;HelloAndroid&gt;</code>&quot;.
                    The superclass is parameterized by an Activity class name.
                    <p>
                        The dialog should now look like this:
                    </p>
                    <a href="{@docRoot}images/testing/hwtest_new_test_class_dialog_complete_callouts.png">
                        <img alt="New Java Class dialog with entries" src="{@docRoot}images/testing/hwtest_new_test_class_dialog_complete_callouts.png" style="height:230px"/>
                    </a>
                </li>
            </ul>
            <p>
                Do not change any of the other settings. Click Finish.
            </p>
        </li>
        <li>
            You now have a new file <code>HelloAndroidTest.java</code> in the project.
            This file contains the class <code>HelloAndroidTest</code>,
            which extends the Activity test case class
            <code>ActivityInstrumentationTestCase2&lt;T&gt;</code>. You parameterize the
            class with <code>HelloAndroid</code>, which is the class name of the activity under test.
        </li>
        <li>
            Open <code>HelloAndroidTest.java</code>. It should look like this:
<pre class="prettyprint">
package com.example.helloandroid.test;

import android.test.ActivityInstrumentationTestCase2;

public class HelloAndroidTest extends ActivityInstrumentationTestCase2&lt;HelloAndroid&gt; {
}
</pre>
        </li>
        <li>
            The test case class depends on the <code>HelloAndroid</code> class, which is not
            yet imported. To import the class, add the following line just before the current
            <code>import</code> statement:
<pre class="prettyprint">
import com.example.helloandroid.HelloAndroid;
</pre>
        </li>
    </ol>
<h3 id="CreateConstructor">Adding the test case constructor</h3>
<p>
    The test case class constructor is used by the Android testing framework when you run the test.
    It calls the super constructor with parameters that tell the framework what Android application
    should be tested.
</p>
<p>
    Add the following constructor method immediately after the class definition:
</p>
<pre class="prettyprint">
    public HelloAndroidTest() {
      super("com.example.helloandroid", HelloAndroid.class);
    }
</pre>
<p>
    Save the file <code>HelloAndroidTest.java</code>.
</p>
<h3 id="CreateSetUp">Adding a setup method</h3>
<p>
    The <code>setUp()</code> method overrides the JUnit {@link junit.framework.TestCase#setUp() setUp()}
    method, which the Android testing framework calls prior to running each test method. You use
    <code>setUp()</code> to initialize variables and prepare the test environment. For this
    test case, the <code>setUp()</code> method starts the Hello, Android application,
    retrieves the text being displayed on the screen, and retrieves the text string in the
    resource file.
</p>
<p>
    First, add the following code immediately after the constructor method:
</p>
<pre class="prettyprint">
    &#064;Override
    protected void setUp() throws Exception {
        super.setUp();
        mActivity = this.getActivity();
        mView = (TextView) mActivity.findViewById(com.example.helloandroid.R.id.textview);
        resourceString = mActivity.getString(com.example.helloandroid.R.string.hello);
    }
</pre>
<p>
    For this code to work, you must also add some class members and another import statement. To
    add the class members, add the following code immediately after the class definition:
</p>
<pre class="prettyprint">
    private HelloAndroid mActivity;
    private TextView mView;
    private String resourceString;
</pre>
<p>
    To add the import statement, add the following statement just after the import for
    <code>android.test.ActivityInstrumentationTestCase2</code>:
</p>
<pre class="prettyprint">
  import android.widget.TextView;
</pre>
<h3 id="CreatePreConditions">Adding a preconditions test</h3>
<p>
    A preconditions test checks the initial application conditions prior to executing other tests.
    It's similar to <code>setUp()</code>, but with less overhead, since it only runs once.
</p>
<p>
    Although a preconditions test can check for a variety of different conditions,
    in this application it only needs to check whether the application under test is
    initialized properly and the target TextView exists.
    To do this, it calls the inherited
    {@link junit.framework.Assert#assertNotNull(Object) assertNotNull()}
    method, passing a reference to the TextView.
    The test succeeds only if the object reference is not null.
</p>
<pre class="prettyprint">
    public void testPreconditions() {
      assertNotNull(mView);
    }
</pre>
<h3 id="CreateText">Adding a unit test</h3>
<p>
    Now add a simple unit test to the test case class.
    The method <code>testText()</code> will call a
    {@link junit.framework.Assert JUnit Assert}
    method to check whether the target TextView is displaying the expected text.
</p>
<p>
    For this example, the test expects that the TextView is
    displaying the string resource that was originally declared for it in HelloAndroid's
    <code>main.xml</code> file, referred to by the resource ID <code>hello</code>.
    The call to
    {@link junit.framework.Assert#assertEquals(String, String) assertEquals(String,String)}
    compares the expected value, read directly from the <code>hello</code>string resource,
    to the text displayed by the TextView, obtained from the
    TextView's <code>getText()</code> method. The test succeeds only if the strings match.
</p>
<p>
    To add this test, add the following code
    immediately after the <code>testPreconditions()</code> method:
</p>
<pre class="prettyprint">
    public void testText() {
      assertEquals(resourceString,(String)mView.getText());
    }
</pre>
<h3 id="CompleteTest">The finished test case class</h3>
<p>
    You have now finished writing the test. This is what the complete test case class
    should look like:
</p>
<pre class="prettyprint">
package com.example.helloandroid.test;

import com.example.helloandroid.HelloAndroid;
import android.test.ActivityInstrumentationTestCase2;
import android.widget.TextView;

public class HelloAndroidTest extends ActivityInstrumentationTestCase2&lt;HelloAndroid&gt; {
    private HelloAndroid mActivity;  // the activity under test
    private TextView mView;          // the activity's TextView (the only view)
    private String resourceString;

    public HelloAndroidTest() {
      super("com.example.helloandroid", HelloAndroid.class);
    }
    &#064;Override
    protected void setUp() throws Exception {
        super.setUp();
        mActivity = this.getActivity();
        mView = (TextView) mActivity.findViewById(com.example.helloandroid.R.id.textview);
        resourceString = mActivity.getString(com.example.helloandroid.R.string.hello);
    }
    public void testPreconditions() {
      assertNotNull(mView);
    }
    public void testText() {
      assertEquals(resourceString,(String)mView.getText());
    }
}
</pre>
<h2 id="RunTest">Running the Tests and Seeing the Results</h2>
<p>
    You can now run the tests you've created against the Hello, Android application. In Eclipse with
    ADT, you run a test application as an <strong>Android JUnit test</strong> rather than a regular
    Android application.
</p>
<p>
    To run the test application as an Android JUnit test, in the Package Explorer right-click
    the HelloAndroidTest project and select <strong>Run As</strong> &gt; <strong>Android JUnit Test</strong>
</p>
    <a href="{@docRoot}images/testing/hwtest_runas_menu_callouts.png">
        <img alt="Menu to run Hello, World as an Android JUnit test"
            src="{@docRoot}images/testing/hwtest_runas_menu_callouts.png" style="height:230px">
    </a>
<p>
    The ADT plugin then launches the test application and the application
    under test on a the target emulator or device. When both applications are running,
    the testing framework runs the tests and reports the results in the JUnit view of Eclipse,
    which appears by default as a tab next to the Package Explorer.
</p>
<p>
    As shown below, the JUnit view shows test results in two separate panes:
    an upper pane summarizes the tests that were run and a lower pane reports the failure traces
    for the tests. In this case, the tests in this example have run successfully, so there is no
    failure reported in the view:
</p>
    <a href="{@docRoot}images/testing/hwtest_junit_success.png">
        <img src="{@docRoot}images/testing/hwtest_junit_success.png"
            alt="JUnit test run success" style="height:230px"/>
    </a>
<p>
    The upper pane summarizes the test:
</p>
    <ul>
        <li>
            &quot;Finished after <em>x</em> seconds&quot;: How long the test took to run.
        </li>
        <li>
            &quot;Runs&quot;: The number of tests run.
        </li>
        <li>
            &quot;Errors:&quot;: The number of program errors and exceptions encountered during
            the test run.
        </li>
        <li>
            &quot;Failures:&quot;: The number of assertion failures encountered during the
            test run.
        </li>
        <li>
            A progress bar. The progress bar extends from left to right as the tests run.
            <p>
              If all the tests succeed, the bar remains green.
              If a test fails, the bar turns from green to red.
            </p>
        </li>
        <li>
            A test method summary. Below the bar, you see a line for each class in the
            test application, labeled by its fully-qualified class name.
            To look at the results for the individual methods in a test case class,
            click the arrow at the left of the class to expand the line.
            You see the name of each test method. To the right of the method name, you see the
            time needed to run that method. You can look at the method's code by
            double-clicking its name.
        </li>
     </ul>
     <p>
        The lower pane contains the failure trace. If all the tests are successful,
        this pane is empty. If some tests fail, then if you select a failed test in the
        upper pane, the lower view contains a stack trace for the test.
     </p>
<h2 id="NextSteps">Next Steps</h2>
<p>
    This simple example test application has shown you how to create a test project,
    create a test class and test cases, and then run the tests against a target application.
    Now that you are familiar with these fundamentals, here are some suggested next steps:
</p>
<p>
    <strong>Learn more about testing on Android</strong>
</p>
<ul>
    <li>
        The
      <a href="{@docRoot}guide/topics/testing/testing_android.html">Testing Android Applications</a>
        document in the <em>Dev Guide</em> provides an overview of how testing on Android works.
        If you are just getting started with Android testing, reading that document will
        help you understand the tools available to you, so that you can develop effective
        tests.
    </li>
</ul>
<p>
    <strong>Learn more about the testing classes available in Android</strong>
</p>
<ul>
    <li>
        For an overview of the types of testing classes you can use,
        browse through the reference documentation for
        {@link android.test.ActivityInstrumentationTestCase2},
        {@link android.test.ProviderTestCase2},
        {@link android.test.ServiceTestCase}, and
        {@link junit.framework.Assert}.
    </li>
</ul>
<p>
    <strong>Explore the Android instrumentation framework</strong>
</p>
<ul>
    <li>
        The {@link android.test.InstrumentationTestRunner} class contains the code that Android uses
        to run tests against an application. The {@link android.test.InstrumentationTestCase} class
        is the base class for test case classes that use additional instrumentation features.
    </li>
</ul>
<p>
    <strong>Follow the Activity Testing tutorial</strong>
</p>
<ul>
    <li>
        The <a href="{@docRoot}resources/tutorials/testing/activity_test.html">Activity Testing</a>
        tutorial is an excellent follow-up to this tutorial.
        It guides you through a more complex testing scenario that you develop against a
        more realistic application.
    </li>
</ul>