单元测试之Robolectric

1. Robolectric

Robolectric允许我们可以在JVM上对Android应用程序进行测试
Robolectric框架允许我们编写单元测试，测试的代码使用了Android API，在本地JVM上运行
Robolectric mock了android.jar文件中的部分Android framework的代码
Robolectric支持资源的处理，例如inflation of views

Robolectric将所有Android类替换为shadow对象。

2. 使用Robolectric

3. Roboelectric test example

@RunWith(RobolectricGradleTestRunner.class)
@Config(constants = BuildConfig.class)
public class MyActivityTest {
    private MainActivity activity;

    @Before
    public void setup() {
        activity = Robolectric.buildActivity(MainActivity.class) .create().get();
    }

    @Test
    public void shouldHaveHappySmiles() throws Exception {
        String hello = new MainActivity().getResources().getString( R.string.hello_world);
        assertThat(hello, equalTo("Hello world!"));
    }

    @Test
    public void checkActivityNotNull() throws Exception {
        assertNotNull(activity);
    }

    @Test
    public void buttonClickShouldStartNewActivity() throws Exception {
        Button button = (Button) activity.findViewById( R.id.button2 );
        button.performClick();
        Intent intent = Shadows.shadowOf(activity).peekNextStartedActivity();
        assertEquals(SecondActivity.class.getCanonicalName(), intent.getComponent().getClassName());
    }

    @Test
    public void testButtonClick() throws Exception {
        MainActivity activity = Robolectric.buildActivity(MainActivity.class) .create().get();
        Button view = (Button) activity.findViewById(R.id.button1);
        assertNotNull(view);
        view.performClick();
        assertThat(ShadowToast.getTextOfLatestToast(), equalTo("Lala") );
    }
}