How can I test an abstract class using Espresso?

Issue

Suppose I make an abstract BaseActivity with a Toolbar, like this:

/**
 * A base activity that handles common functionality in the app. 
 * This includes the Toolbar
 */
public abstract class BaseActivity extends AppCompatActivity {
    // Primary toolbar
    private Toolbar mToolbar;

    @Override
    public void setContentView(int layoutResId) {
        super.setContentView(layoutResId);
        setToolbar();
    }

    private void setToolbar() {
        if (mToolbar == null) {
            mToolbar = (Toolbar) findViewById(R.id.toolbar);
            if (mToolbar != null) {              
                mToolbar.setNavigationContentDescription(getResources().getString(
                    R.string.navigation_drawer_description_ally));
            setSupportActionBar(mToolbar);
            }
        }
    }
}

And a MainActivity that extends this BaseActivity, like this:

public class MainActivity extends BaseActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }
}

The layouts are:

toolbar.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.Toolbar
xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/toolbar"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="?attr/colorPrimary"
    android:elevation="@dimen/spacing_tiny"
    android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
    android:popupTheme="@style/ThemeOverlay.AppCompat.Light"
    android:fitsSystemWindows="true"
    android:minHeight="?attr/actionBarSize"
    >

</android.support.v7.widget.Toolbar>

activity_main.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity"
    >

    <include
        layout="@layout/toolbar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        />

</LinearLayout>

My question is: How can I test BaseActivity using espresso? To, for example, check if the Toolbar exists?

Solution

You should create a TestActivity for testing your abstract BaseActivity Class. But remember, this class should only override the necessary method and code to avoid any effect to the BaseActivity class.

public class TestActivity extends BaseActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }
}

And then you can use your Espresso to

@RunWith(AndroidJUnit4.class)
@SmallTest
public class BaseActivityTest {
    @Rule
    public ActivityTestRule<TestActivity> mTestActivityActivityTestRule = new ActivityTestRule<TestActivity>(TestActivity.class, true, false);
    @Before
    public void set() {
        //setup your things
    }
    @Test
    public void testRequest1() {
        mTestActivityActivityTestRule.launchActivity(new Intent());
    }
}

Answered By - Long Ranger