1.1. How to test Android applications

1.2. Unit tests vs functional tests

1.3. JUnit 3

1.4. Running tests on a server without display

2.1. Instrumentation

2.2. How the Android system executes tests

3.1. Android assertion and mock classes

3.2. Android test classes

3.3. Android test groups

3.4. Flaky tests

5.1. ActivityUnitTestCase

package com.vogella.android.test.simpleactivity;

import android.app.Activity;

import android.content.Intent;

import android.os.Bundle;

import android.view.View;

public class MainActivity extends Activity {

  @Override

  protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_main);

  }

  public void onClick(View view) {

    Intent intent = new Intent(this, SecondActivity.class);

    intent.putExtra("URL", "http://www.vogella.com");

    startActivity(intent);

  }

} 

package com.vogella.android.test.simpleactivity.test;

import android.content.Intent;

import android.test.TouchUtils;

import android.test.suitebuilder.annotation.SmallTest;

import android.widget.Button;

import com.vogella.android.test.simpleactivity.MainActivity;

public class MainActivityUnitTest extends

    android.test.ActivityUnitTestCase<MainActivity> {

  private int buttonId;

  private MainActivity activity;

  public MainActivityUnitTest() {

    super(MainActivity.class);

  }

  @Override

  protected void setUp() throws Exception {

    super.setUp();

    Intent intent = new Intent(getInstrumentation().getTargetContext(),

        MainActivity.class);

    startActivity(intent, null, null);

    activity = getActivity();

  }

  @SmallTest

  public void testLayout() {

    buttonId = com.vogella.android.test.simpleactivity.R.id.button1;

    assertNotNull(activity.findViewById(buttonId));

    Button view = (Button) activity.findViewById(buttonId);

    assertEquals("Incorrect label of the button", "Start", view.getText());

  }

  @SmallTest

  public void testIntentTriggerViaOnClick() {

    buttonId = com.vogella.android.test.simpleactivity.R.id.button1;

    Button view = (Button) activity.findViewById(buttonId);

    assertNotNull("Button not allowed to be null", view);

    // You would call the method directly via

    getActivity().onClick(view);

    // TouchUtils cannot be used, only allowed in

    // InstrumentationTestCase or ActivityInstrumentationTestCase2 

    // Check the intent which was started

    Intent triggeredIntent = getStartedActivityIntent();

    assertNotNull("Intent was null", triggeredIntent);

    String data = triggeredIntent.getExtras().getString("URL");

    assertEquals("Incorrect data passed via the intent",

        "http://www.vogella.com", data);

  }

  @Override

  protected void tearDown() throws Exception {

    super.tearDown();

  }

} 

package com.vogella.android.test.simpleactivity.test;

import android.app.Activity;

import android.app.Instrumentation;

import android.app.Instrumentation.ActivityMonitor;

import android.test.ActivityInstrumentationTestCase2;

import android.test.TouchUtils;

import android.test.ViewAsserts;

import android.view.KeyEvent;

import android.view.View;

import android.widget.Button;

import android.widget.TextView;

import com.vogella.android.test.simpleactivity.R;

import com.vogella.android.test.simpleactivity.MainActivity;

import com.vogella.android.test.simpleactivity.SecondActivity;

public class MainActivityFunctionalTest extends

    ActivityInstrumentationTestCase2<MainActivity> {

  private MainActivity activity;

  public MainActivityFunctionalTest() {

    super(MainActivity.class);

  }

  @Override

  protected void setUp() throws Exception {

    super.setUp();

    setActivityInitialTouchMode(false);

    activity = getActivity();

  }

  public void testStartSecondActivity() throws Exception {

    // Add monitor to check for the second activity

    ActivityMonitor monitor = getInstrumentation().addMonitor(SecondActivity.class.getName(), null, false);

    // Find button and click it

    Button view = (Button) activity.findViewById(R.id.button1);

    TouchUtils.clickView(this, view);

    // To click on a click, e.g. in a listview

    // listView.getChildAt(0);

    // Wait 2 seconds for the start of the activity

    SecondActivity startedActivity = (SecondActivity) monitor

        .waitForActivityWithTimeout(2000);

    assertNotNull(startedActivity);

    // Search for the textView

    TextView textView = (TextView) startedActivity.findViewById(R.id.resultText);

    // Check that the TextView is on the screen

    ViewAsserts.assertOnScreen(startedActivity.getWindow().getDecorView(),

        textView);

    // Validate the text on the TextView

    assertEquals("Text incorrect", "Started", textView.getText().toString());

    // Press back and click again

    this.sendKeys(KeyEvent.KEYCODE_BACK);

    TouchUtils.clickView(this, view);

  }

} 

package com.vogella.android.test.simpleactivity.test;

import android.app.Activity;

import android.app.Instrumentation;

import android.app.Instrumentation.ActivityMonitor;

import android.test.ActivityInstrumentationTestCase2;

import android.test.TouchUtils;

import android.test.UiThreadTest;

import android.test.ViewAsserts;

import android.view.KeyEvent;

import android.view.View;

import android.widget.Button;

import android.widget.TextView;

import com.vogella.android.test.simpleactivity.R;

import com.vogella.android.test.simpleactivity.MainActivity;

import com.vogella.android.test.simpleactivity.SecondActivity;

public class SecondActivityFunctionalTest extends

    ActivityInstrumentationTestCase2<SecondActivity> {

  private static final String NEW_TEXT = "new text";

  public SecondActivityFunctionalTest() {

    super(SecondActivity.class);

  }

  public void testSetText() throws Exception {

    SecondActivity activity = getActivity();

    // search for the textView

    final TextView textView = (TextView) activity

        .findViewById(R.id.resultText);

    // set text

    getActivity().runOnUiThread(new Runnable() {

      @Override

      public void run() {

        textView.setText(NEW_TEXT);

      }

    });

    getInstrumentation().waitForIdleSync();

    assertEquals("Text incorrect", NEW_TEXT, textView.getText().toString());

  }

  @UiThreadTest

  public void testSetTextWithAnnotation() throws Exception {

    SecondActivity activity = getActivity();

    // search for the textView

    final TextView textView = (TextView) activity

        .findViewById(R.id.resultText);

    textView.setText(NEW_TEXT);

    assertEquals("Text incorrect", NEW_TEXT, textView.getText().toString());

  }

} 

To test an service you use the ServiceTestCase class. It provides the startService() and bindService() methods to interact with the service. The bindService() return immediately a IBinder object without callback.

Testing asynchronous processing in services is a challenge as the duration of this processing may vary.

It is good practice to test if the service handles correctly multiple calls from startService(). Only the first call of startService() triggers the onCreate() of the service but all calls trigger a call to onStartCommand() of the service.

To test an content provider you use the ProviderTestCase2 class. ProviderTestCase2 instantiates automatically the provider under test and inserts an IsolatedContext object which is isolated from the Android system but still allows file and database access.

The usage of the IsolatedContext object ensures that your provider test does not affect the real device.

ProviderTestCase2 provides also access to a MockContentResolver via the getMockCOnktentResolver() method.

You should test all operations of the provider and also what happens if the provider is called with an invalid URI or with an invalid projection.