Complete reference for Android Testing with examples.
- Introduction
- Local Tests
- Android
- References
- Testing forces you to think in a different way and implicitly makes your code cleaner in the process.
- You feel more confident about your code if it has tests.
- Shiny green status bars and cool reports detailing how much of your code is covered are both consequences of writing tests.
- Regression testing is made a lot easier, as automated tests would pick up the bugs first.
A unit test generally exercises the functionality of the smallest possible unit of code (which could be a method, class, or component) in a repeatable way.
Tools that are used to do this testing:
- JUnit – normal test assertions.
- Mockito – mocking out other classes that are not under test.
- PowerMock – mocking out static classes such as Android Environment class etc.
A UI Test or Instrumentation Test mocks typical user interactions with your app. Clicking on buttons, typing in text are some of the things UI Tests can complete.
- Espresso – Used for testing within your app, selecting items, making sure something is visible.
- UIAutomator – Used for testing interaction between different apps.
There are other tools that are available for this kind of testing such as Robotium, Appium, Calabash, Robolectric.
public class Calculator {
public int add(int op1, int op2) {
return op1 + op2;
}
public int diff(int op1, int op2) {
return op1 - op2;
}
public double div(int op1, int op2) {
// if (op2 == 0) return 0;
return op1 / op2;
}
}public class CalculatorTest {
private Calculator calculator;
@Before
public void setup() {
calculator = new Calculator();
System.out.println("Ready for testing!");
}
@After
public void cleanup() {
System.out.println("Done with unit test!");
}
@BeforeClass
public static void testClassSetup() {
System.out.println("Getting test class ready");
}
@AfterClass
public static void testClassCleanup() {
System.out.println("Done with tests");
}
@Test
public void testAdd() {
calculator = new Calculator();
int total = calculator.add(4, 5);
assertEquals("Calculator is not adding correctly", 9, total);
}
@Test
public void testDiff() {
calculator = new Calculator();
int total = calculator.diff(9, 2);
assertEquals("Calculator is not subtracting correctly", 7, total);
}
@Test
public void testDiv() {
calculator = new Calculator();
double total = calculator.div(9, 3);
assertEquals("Calculator is not dividing correctly", 3.0, total, 0.0);
}
}@Ignore
@Test(expected = java.lang.ArithmeticException.class)
public void testDivWithZeroDivisor() {
calculator = new Calculator();
double total = calculator.div(9, 0);
assertEquals("Calculator is not handling division by zero correctly", 0.0, total, 0.0);
}JUnit provides overloaded assertion methods for all primitive types and Objects and arrays (of primitives or Objects). The parameter order is expected value followed by actual value. Optionally the first parameter can be a String message that is output on failure. There is a slightly different assertion, assertThat that has parameters of the optional failure message, the actual value, and a Matcher object. Note that expected and actual are reversed compared to the other assert methods.
public class AssertTests {
@Test
public void testAssertArrayEquals() {
byte[] expected = "trial".getBytes();
byte[] actual = "trial".getBytes();
assertArrayEquals("failure - byte arrays not same", expected, actual);
}
@Test
public void testAssertEquals() {
assertEquals("failure - strings are not equal", "text", "text");
}
@Test
public void testAssertFalse() {
assertFalse("failure - should be false", false);
}
@Test
public void testAssertNotNull() {
assertNotNull("should not be null", new Object());
}
@Test
public void testAssertNotSame() {
assertNotSame("should not be same Object", new Object(), new Object());
}
@Test
public void testAssertNull() {
assertNull("should be null", null);
}
@Test
public void testAssertSame() {
Integer aNumber = Integer.valueOf(768);
assertSame("should be same", aNumber, aNumber);
}
// JUnit Matchers assertThat
@Test
public void testAssertThatBothContainsString() {
assertThat("albumen", both(containsString("a")).and(containsString("b")));
}
@Test
public void testAssertThatHasItems() {
assertThat(Arrays.asList("one", "two", "three"), hasItems("one", "three"));
}
@Test
public void testAssertThatEveryItemContainsString() {
assertThat(Arrays.asList(new String[] { "fun", "ban", "net" }), everyItem(containsString("n")));
}
// Core Hamcrest Matchers with assertThat
@Test
public void testAssertThatHamcrestCoreMatchers() {
assertThat("good", allOf(equalTo("good"), startsWith("good")));
assertThat("good", not(allOf(equalTo("bad"), equalTo("good"))));
assertThat("good", anyOf(equalTo("bad"), equalTo("good")));
assertThat(7, not(CombinableMatcher.<Integer> either(equalTo(3)).or(equalTo(4))));
assertThat(new Object(), not(sameInstance(new Object())));
}
@Test
public void testAssertTrue() {
assertTrue("failure - should be true", true);
}
}public class HamcrestTest {
@Test
public void testWithAsserts() {
List<String> list = generateStingList();
assertTrue(list.contains("android"));
assertTrue(list.contains("context"));
assertTrue(list.size() > 4);
assertTrue(list.size() < 13);
}
@Test
public void testWithBigAssert() {
List<String> list = generateStingList();
assertTrue(list.contains("android") && list.contains("context") && list.size() > 3 && list.size() < 12);
}
@Test
public void testWithHamcrest() {
List<String> list = generateStingList();
assertThat(list, (hasItems("android", "context")));
assertThat(list, allOf(hasSize(greaterThan(3)), hasSize(lessThan(12))));
}
@Test
public void testFailureWithAsserts() {
List<String> list = generateStingList();
assertTrue(list.contains("android"));
assertTrue(list.contains("service"));
assertTrue(list.size() > 3);
assertTrue(list.size() < 12);
}
@Test
public void testFailureWithHamcrest() {
List<String> list = generateStingList();
assertThat(list, (hasItems("android", "service")));
assertThat(list, allOf(hasSize(greaterThan(3)), hasSize(lessThan(12))));
}
@Test
public void testTypeSafety() {
// assertThat("123", equalTo(123));
// assertThat(123, equalTo("123"));
}
private List<String> generateStingList() {
String[] sentence = {"android", "context", "service", "manifest", "layout", "resource", "broadcast", "receiver", "gradle"};
return Arrays.asList(sentence);
}
}public class CalculatorWithTestName {
@Rule
public TestName name = new TestName();
@Test
public void testAdd() {
Calculator calculator = new Calculator();
int total = calculator.add(4, 5);
assertEquals(name.getMethodName() + " adding incorrectly", 9, total);
}
@Test
public void testDiff() {
Calculator calculator = new Calculator();
int total = calculator.diff(12, 7);
assertEquals(name.getMethodName() + " subtracting incorrectly", 5, total);
}
}RESTMock is a library working on top of Square's okhttp/MockWebServer. It allows you to specify Hamcrest matchers to match HTTP requests and specify what response to return. It is as easy as:
RESTMockServer.whenGET(pathContains("users/defunkt"))
.thenReturnFile(200, "users/defunkt.json");It's good to start server before the tested application starts, there are few methods:
To make it simple you can just use the predefined RESTMockTestRunner in your UI tests. It extends AndroidJUnitRunner:
defaultConfig {
...
testInstrumentationRunner 'io.appflate.restmock.android.RESTMockTestRunner'
}If you have your custom test runner and you can't extend RESTMockTestRunner, you can always just call the RESTMockServerStarter. Actually RESTMockTestRunner is doing exactly the same thing:
public class MyAppTestRunner extends AndroidJUnitRunner {
...
@Override
public void onCreate(Bundle arguments) {
super.onCreate(arguments);
RESTMockServerStarter.startSync(new AndroidAssetsFileParser(getContext()),new AndroidLogger());
...
}
...
}By default, the RESTMockTestRunner uses AndroidAssetsFileParser as a mocks file parser, which reads the files from the assets folder. To make them visible for the RESTMock you have to put them in the correct folder in your project, for example:
.../src/androidTest/assets/users/defunkt.json
This can be accessed like this:
RESTMockServer.whenGET(pathContains("users/defunkt"))
.thenReturnFile(200, "users/defunkt.json");If the response You wish to return is simple, you can just specify a string:
RESTMockServer.whenGET(pathContains("users/defunkt"))
.thenReturnString(200, "{}");If you wish to have a greater control over the response, you can pass the MockResponse
RESTMockServer.whenGET(pathContains("users/defunkt")).thenReturn(new MockResponse().setBody("").setResponseCode(401).addHeader("Header","Value"));You can either use some of the predefined matchers from RequestMatchers util class, or create your own. remember to extend from RequestMatcher
The most important step, in order for your app to communicate with the testServer, you have to specify it as an endpoint for all your API calls. For that, you can use the RESTMockServer.getUrl(). If you use Retrofit, it is as easy as:
RestAdapter adapter = new RestAdapter.Builder()
.baseUrl(RESTMockServer.getUrl())
...
.build();It is possible to verify which requests were called and how many times thanks to RequestsVerifier. All you have to do is call one of these:
//cheks if the GET request was invoked exactly 2 times
RequestsVerifier.verifyGET(pathEndsWith("users")).exactly(2);
//cheks if the GET request was invoked at least 3 times
RequestsVerifier.verifyGET(pathEndsWith("users")).atLeast(3);
//cheks if the GET request was invoked exactly 1 time
RequestsVerifier.verifyGET(pathEndsWith("users")).invoked();
//cheks if the GET request was never invoked
RequestsVerifier.verifyGET(pathEndsWith("users")).never();RESTMock supports logging events. You just have to provide the RESTMock with the implementation of RESTMockLogger. For Android there is an AndroidLogger implemented already. All you have to do is use the RESTMockTestRunner or call
RESTMockServerStarter.startSync(new AndroidAssetsFileParser(getContext()),new AndroidLogger());or
RESTMockServer.enableLogging(RESTMockLogger)
RESTMockServer.disableLogging()public class MainActivityTestRule<A extends Activity> extends ActivityTestRule<A> {
public MainActivityTestRule(Class<A> activityClass) {
super(activityClass);
}
@Override
protected Intent getActivityIntent() {
Log.e("MainActivityTestRule", "Prepare the activity's intent");
return super.getActivityIntent();
}
@Override
protected void beforeActivityLaunched() {
Log.e("MainActivityTestRule", "Execute before the activity is launched");
super.beforeActivityLaunched();
}
@Override
protected void afterActivityLaunched() {
Log.e("MainActivityTestRule", "Execute after the activity has been launched");
super.afterActivityLaunched();
}
@Override
protected void afterActivityFinished() {
Log.e("MainActivityTestRule", "Cleanup after it has finished");
super.afterActivityFinished();
}
@Override
public A launchActivity(Intent startIntent) {
Log.e("MainActivityTestRule", "Launching the activity");
return super.launchActivity(startIntent);
}
}public class SampleServiceTestRule extends ServiceTestRule {
@Override
public void startService(Intent intent) throws TimeoutException {
Log.e("SampleServiceTestRule", "start the service");
super.startService(intent);
}
@Override
public IBinder bindService(Intent intent) throws TimeoutException {
Log.e("SampleServiceTestRule", "binding the service");
return super.bindService(intent);
}
@Override
protected void beforeService() {
Log.e("SampleServiceTestRule", "work before the service starts");
super.beforeService();
}
@Override
protected void afterService() {
Log.e("SampleServiceTestRule", "work after the service has started");
super.afterService();
}
}@RunWith(AndroidJUnit4.class)
public class MainActivityTest {
@Rule
public MainActivityTestRule<MainActivity> mainActivityActivityTestRule = new MainActivityTestRule<MainActivity>(MainActivity.class);
@Test
public void testUI() {
Activity activity = mainActivityActivityTestRule.getActivity();
assertNotNull(activity.findViewById(R.id.text_hello));
TextView helloView = (TextView) activity.findViewById(R.id.text_hello);
assertTrue(helloView.isShown());
assertEquals("Hello World!", helloView.getText());
assertEquals(InstrumentationRegistry.getTargetContext().getString(R.string.hello_world), helloView.getText());
assertNull(activity.findViewById(android.R.id.button1));
}
}@RunWith(AndroidJUnit4.class)
public class SampleServiceTest {
@Rule
public SampleServiceTestRule myServiceRule = new SampleServiceTestRule();
@Test
public void testService() throws TimeoutException {
myServiceRule.startService(new Intent(InstrumentationRegistry.getTargetContext(), SampleService.class));
}
@Test
public void testBoundService() throws TimeoutException {
IBinder binder = myServiceRule.bindService(
new Intent(InstrumentationRegistry.getTargetContext(), SampleService.class));
SampleService service = ((SampleService.LocalBinder) binder).getService();
// Do work with the service
assertNotNull("Bound service is null", service);
}
}@Test
@RequiresDevice
public void testRequiresDevice() {
Log.d("Test Filters", "This test requires a device");
Activity activity = activityTestRule.getActivity();
assertNotNull("MainActivity is not available", activity);
}
@Test
@SdkSuppress(minSdkVersion = 30)
public void testMinSdkVersion() {
Log.d("Test Filters", "Checking for min sdk >= 30");
Activity activity = activityTestRule.getActivity();
assertNotNull("MainActivity is not available", activity);
}
@Test
@SdkSuppress(minSdkVersion = Build.VERSION_CODES.LOLLIPOP)
public void testMinBuild() {
Log.d("Test Filters", "Checking for min build > Lollipop");
Activity activity = activityTestRule.getActivity();
assertNotNull("MainActivity is not available", activity);
}
@Test
@SmallTest
public void testSmallTest() {
Log.d("Test Filters", "this is a small test");
Activity activity = activityTestRule.getActivity();
assertNotNull("MainActivity is not available", activity);
}
@Test
@LargeTest
public void testLargeTest() {
Log.d("Test Filters", "This is a large test");
Activity activity = activityTestRule.getActivity();
assertNotNull("MainActivity is not available", activity);
}@Test
public void testEspresso() {
ViewInteraction interaction =
onView(allOf(withId(R.id.editText),
withText("this is a test"),
hasFocus()));
interaction.perform(replaceText("how about some new text"));
ViewInteraction interaction2 =
onView(allOf(withId(R.id.editText),
withText("how about some new text")));
interaction2.check(matches(hasFocus()));
}
@Test
public void testEspressoSimplified() {
onView(allOf(withId(R.id.editText),
withText("this is a test"),
hasFocus())).perform(replaceText("how about some new text"));
onView(allOf(withId(R.id.editText),
withText("how about some new text"))).check(matches(hasFocus()));
}MainActivityRoboelectricTest.java
@RunWith(RobolectricGradleTestRunner.class)
@Config(constants = BuildConfig.class)
public class MainActivityRoboelectricTest {
private MainActivity activity;
@Before
public void setup() {
activity = Robolectric.setupActivity(MainActivity.class);
}
@Test
public void clickButton() {
Button button = (Button) activity.findViewById(R.id.button);
assertNotNull("test button could not be found", button);
assertTrue("button does not contain text 'Click Me!'", "Click Me".equals(button.getText()));
}
}public class MainActivityRobotiumTest {
private Solo solo;
@Rule
public ActivityTestRule<MainActivity> activityTestRule =
new ActivityTestRule<>(MainActivity.class);
public void setUp() {
solo = new Solo(InstrumentationRegistry.getInstrumentation(),
activityTestRule.getActivity());
}
public void tearDown() {
solo.finishOpenedActivities();
}
@Test
public void testPushClickMe() {
solo.waitForActivity(MainActivity.class);
solo.assertCurrentActivity("MainActivity is not displayed", MainActivity.class);
assertTrue("This is a test in EditText is not displayed",
solo.searchText("this is a test"));
solo.clickOnButton("Click Me");
assertTrue("You clicked me text is not displayed in the EditText",
solo.searchText("you clicked me!"));
}
}@Test
public void testPressBackButton() {
UiDevice.getInstance(InstrumentationRegistry.getInstrumentation()).pressBack();
}
@Test
@Ignore
public void testUiDevice() throws RemoteException {
UiDevice device = UiDevice.getInstance(
InstrumentationRegistry.getInstrumentation());
if (device.isScreenOn()) {
device.setOrientationLeft();
device.openNotification();
}
}
@Test
public void testUiAutomatorAPI() throws UiObjectNotFoundException, InterruptedException {
UiDevice device = UiDevice.getInstance(InstrumentationRegistry.getInstrumentation());
UiSelector editTextSelector = new UiSelector().className("android.widget.EditText").text("this is a test").focusable(true);
UiObject editTextWidget = device.findObject(editTextSelector);
editTextWidget.setText("this is new text");
Thread.sleep(2000);
UiSelector buttonSelector = new UiSelector().className("android.widget.Button").text("Click Me").clickable(true);
UiObject buttonWidget = device.findObject(buttonSelector);
buttonWidget.click();
Thread.sleep(2000);
}# Imports the monkeyrunner modules
from com.android.monkeyrunner import MonkeyRunner, MonkeyDevice, MonkeyImage
# Alert the user a MonkeyRunner script is about to execute
MonkeyRunner.alert("Monkeyrunner about to execute","Monkeyrunner","OK")
# Connects to the current emulator
emulator= MonkeyRunner.waitForConnection()
# Install the Android app package and test package
emulator.installPackage('./app/build/outputs/apk/app-debug-unaligned.apk')
emulator.installPackage('./app/build/outputs/apk/app-debug-androidTest-unaligned.apk')
# sets a variable with the package's internal name
package = 'in.ravidsrk.sample'
# sets a variable with the name of an Activity in the package
activity = 'in.ravidsrk.sample.MainActivity'
# sets the name of the component to start
runComponent = package + '/' + activity
# Runs the component
emulator.startActivity(runComponent)
# wait for the screen to fully come up
MonkeyRunner.sleep(2.0)
# Takes a screenshot
snapshot = emulator.takeSnapshot()
# Writes the screenshot to a file
snapshot.writeToFile('mainactivity.png','png')
# Alert the user a testing is about to be run by MonkeyRunner
MonkeyRunner.alert("Instrumented test about to execute","Monkeyrunner","OK")
#kick off the instrumented test
emulator.shell('am instrument -w in.ravidsrk.sample.test/android.support.test.runner.AndroidJUnitRunner')
# return to the emulator home screen
emulator.press('KEYCODE_HOME','DOWN_AND_UP')- https://github.com/junit-team/junit4/wiki/assertions
- https://github.com/googlesamples/android-testing
- https://riggaroo.co.za/introduction-automated-android-testing/
- http://robolectric.org
- https://github.com/robolectric/robolectric
- https://www.bignerdranch.com/blog/triumph-android-studio-1-2-sneaks-in-full-testing-support
- https://github.com/mutexkid/android-studio-robolectric-example
- http://blog.nikhaldimann.com/2013/10/10/robolectric-2-2-some-pages-from-the-missing-manual
- https://corner.squareup.com/2013/04/the-resurrection-of-testing-for-android.html
- http://simpleprogrammer.com/2010/07/27/the-best-way-to-unit-test-in-android/
- https://youtu.be/f7ihSQ44WO0?t=15m11s
- https://code.google.com/p/android-test-kit
- https://developer.android.com/training/testing/ui-testing/espresso-testing.html
- https://github.com/vgrec/EspressoExamples
- https://github.com/designatednerd/Wino
- http://chiuki.github.io/advanced-android-espresso/#/
- http://www.vogella.com/tutorials/AndroidTestingEspresso/article.html
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