#单元测试

1.环境配置：

//add for test
testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"

//add for test
androidTestCompile 'com.android.support.test.espresso:espresso-core:2.2.2', {
    exclude group: 'com.android.support', module: 'support-annotations'
}

2.界面布局：

...

<TextView
    android:id="@+id/textView"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Hello World!" />
<EditText
    android:id="@+id/editText"
    android:layout_width="match_parent"
    android:layout_height="wrap_content" />
<Button
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:text="SAY HFLLO"
    android:onClick="sayHello"/>

java代码：

public class mainActivity extends AppCompatActivity {
    private TextView textView;
    private EditText editText;
    private Button btn;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_fullscreen);

    }

    public void sayHello(View view){
        TextView textView= (TextView) findViewById(R.id.textView);
        EditText editText= (EditText) findViewById(R.id.editText);
        textView.setText("Hello,"+editText.getText().toString()+"!");
    }
}

 测试：

public class MainActivityTest {
    private static final String STRING_TO_BE_TYPED = "Peter";
    @Rule
    public ActivityTestRule<MainActivity> mActivityRule = new ActivityTestRule<>(MainActivity.class);
    @Test
    public void sayHello() throws Exception {
            onView(withId(R.id.editText))
                    .perform(typeText(STRING_TO_BE_TYPED),
                            closeSoftKeyboard());

            onView(withText("Say hello!")).perform(click());

            String expectedText = "Hello," + STRING_TO_BE_TYPED + "!";
            onView(withId(R.id.textView))
                    .check(matches(withText(expectedText)));

    }

}