Android TDD Part 9— UI Test: Espresso

Running UI tests take more time than unit tests, but we still need it. Espresso is an Android UI test framework. you can get a view by id or text, then click a button or type data in an EditText to verify behavior is correct.

Find a view

Finding a view by its id

onView(withId(R.id.someId)).perform(typeText("Some Text"))

Finding a view by matching a text.

onView(withText("Some text")).check(matches(isDisplayed()))

Clicking a view by its id

onView(withId(R.id.button)).perform(click())

Espresso dependencies

Add the following dependencies on app’s build.gradle file.

dependencies {
    androidTestImplementation 'com.android.support.test:rules:1.0.2'
    androidTestImplementation 'com.android.support.test:runner:1.0.2'
    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
}

Write UI test

Use previous sample: sing up.UI test is located at androidTest just like the Instrumented test. Create a RegisterTest class.

@LargeTest annotation indicates that the test duration can be more than 1 second.

@LargeTest
class RegisterTest {
    
}

To test MainActivity, use ActivityTestRule to get an Activity instance.

class RegisterTest {
    @Rule
    @JvmField
    var activityActivityTestRule 
      = ActivityTestRule(MainActivity::class.java)
}

Write a UI test for register success:

1. Type a123456789 on loginId.
2. Type a111111111 on password.
3. Click the send button.
4. Verify contains a text “Sign Up Success” on view.

@Test
fun rightPassword_should_startActivity() {
   
    //type "a123456789" on loginId
    onView(withId(R.id.loginId)).perform(typeText("a123456789")
      , ViewActions.closeSoftKeyboard())
    
    //type "a111111111" on password
    onView(withId(R.id.password)).perform(typeText("a111111111")
      , ViewActions.closeSoftKeyboard())
    //click send button
    onView(withId(R.id.send)).perform(click())
    //verify screen should display "Sign Up Success"
    onView(withText("Sign Up Success"))
      .check(matches(isDisplayed()))
}

Click the green triangle to run the test. You’ll see the emulator is running test.

Typing the wrong password should alert.

@Test
fun wrongPassword_should_alert() {
    
    //type login id
    onView(withId(R.id.loginId)).perform(typeText("a123456789")
      , ViewActions.closeSoftKeyboard())
    //type password
    onView(withId(R.id.password)).perform(typeText("1234")
      , ViewActions.closeSoftKeyboard())
    //click send button
    onView(withId(R.id.send)).perform(click())
    
    //register fail should alert
    onView(withText("Error"))
        .inRoot(isDialog())
        .check(matches(isDisplayed()))
}

Run the test and pass it.

Let’s refactor the code. The flowering codes show how to type a123456789 on loginId and type a111111111 on password.

@Test
fun rightPassword_should_startActivity() {
    onView(withId(R.id.loginId)).perform(typeText("a123456789"), ViewActions.closeSoftKeyboard())
    onView(withId(R.id.password)).perform(typeText("a111111111"), ViewActions.closeSoftKeyboard())    ...
}

Extract these two lines of codes to the inputRightRegisterData method. In this test case, we only need to know typing right id and password should start an Activity, the detail should be encapsulation.

@Test
fun rightPassword_should_startActivity() {
    inputRightRegisterData()
    ...
}

Same as wrong password tests case.

@Test
fun wrongPassword_should_alert() {
    inputWrongRegisterData()
    ...
}

Github:
https://github.com/evanchen76/AndroidTDD_uitestsample

Reference:
https://developer.android.com/training/testing/espresso

Next: Android TDD Part 10 — Robolectric

Android TDD Part 10— Robolectric