Migrating From Android Test Classes

Workflow

• 1. Flip the runner first. Set android.defaultConfig.testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner" and add the AndroidX Test deps. Until this is done, JUnit4/Espresso/ActivityScenario cannot run. (../../../instrumentation/runner/running-instrumented-tests-with-androidjunit4/SKILL.md.)

• 2. Convert one test class at a time, JUnit3 → JUnit4. Drop extends …TestCase, add @RunWith(AndroidJUnit4::class), annotate test methods @Test, convert setUp()/tearDown() overrides to @Before/@After (no super call), and rename testFoo → foo if you like. Replace each legacy accessor with its AndroidX equivalent from the table.

• 3. Replace base-class superpowers with explicit AndroidX entry points. getContext() → ApplicationProvider.getApplicationContext(); getInstrumentation() → InstrumentationRegistry.getInstrumentation(); getActivity() → ActivityScenario + onActivity { }; getService() → ServiceTestRule.bindService(...).

• 4. Swap the assertion helpers. MoreAsserts.* → Truth/kotlin.test; ViewAsserts.* → Espresso ViewAssertions; TouchUtils.* → Espresso ViewActions.

• 5. Swap the mock contexts. Anything extending android.test.mock.MockContext/MockResources/MockPackageManager → a real test context where possible, otherwise a Mockito/MockK mock. (../../../jvm-tests/mocking/mocking-with-mockito/SKILL.md.)

• 6. Delete the legacy imports and confirm nothing references android.test.* or android.test.mock.* any more. A clean module compiles with zero import android.test. lines.

Patterns

Pattern: ActivityInstrumentationTestCase2 → ActivityScenario

// WRONG — deprecated base class
class LoginActivityTest : ActivityInstrumentationTestCase2<LoginActivity>(LoginActivity::class.java) {
    fun testTitleShown() {
        val activity = activity                       // getActivity()
        assertEquals("Sign in", activity.title)
    }
}
// WRONG because: android.test.ActivityInstrumentationTestCase2 is @Deprecated; it ties the test to
// the legacy InstrumentationTestRunner, blocks JUnit4/Espresso, and getActivity() leaks the Activity
// off the main thread.

// RIGHT — ActivityScenario + JUnit4
@RunWith(AndroidJUnit4::class)
class LoginActivityTest {
    @get:Rule val scenario = ActivityScenarioRule(LoginActivity::class.java)

    @Test fun titleShown() {
        scenario.scenario.onActivity { activity ->
            assertEquals("Sign in", activity.title)
        }
        onView(withId(R.id.title)).check(matches(withText("Sign in")))   // or assert via Espresso
    }
}

Pattern: AndroidTestCase → @RunWith(AndroidJUnit4) + ApplicationProvider

// WRONG
class FormatterTest : AndroidTestCase() {
    fun testCurrency() {
        val s = CurrencyFormatter(context).format(1099)   // getContext()
        assertEquals("$10.99", s)
    }
}
// WRONG because: android.test.AndroidTestCase is @Deprecated; getContext() and the TestCase shape
// are the legacy world.

// RIGHT
@RunWith(AndroidJUnit4::class)
class FormatterTest {
    private val context: Context = ApplicationProvider.getApplicationContext()

    @Test fun currency() {
        assertEquals("$10.99", CurrencyFormatter(context).format(1099))
    }
}

Pattern: MoreAsserts / TouchUtils calls

// WRONG
MoreAsserts.assertContentsInAnyOrder(ids, 3L, 1L, 2L)         // android.test.MoreAsserts (deprecated)
TouchUtils.tapView(this, listView)                            // android.test.TouchUtils (deprecated)
ViewAsserts.assertOnScreen(rootView, listView)                // android.test.ViewAsserts (deprecated)

// RIGHT
assertThat(service.ids()).containsExactly(1L, 2L, 3L)         // Google Truth (order-insensitive)
onView(withId(R.id.list)).perform(click())                    // Espresso ViewActions
onView(withId(R.id.list)).check(matches(isCompletelyDisplayed()))   // Espresso ViewAssertions

Pattern: android.test.mock.MockContext subclass → real context or Mockito

// WRONG
class FakeContext : MockContext() {                            // android.test.mock.MockContext (deprecated)
    override fun getPackageName() = "com.example"
    // every other method throws UnsupportedOperationException
}

// RIGHT — a real test context if the SUT just reads from it
val context: Context = ApplicationProvider.getApplicationContext()

// RIGHT — a mock if you must control specific calls in isolation
val context = mock<Context> { on { packageName } doReturn "com.example" }

Mandatory rules

• MUST NOT add new tests using any android.test.* or android.test.mock.* class — all are @Deprecated. New tests use AndroidX Test (AndroidJUnit4, ActivityScenario, ServiceTestRule, ProviderTestRule, Espresso) and org.junit/kotlin.test assertions.
• MUST switch testInstrumentationRunner to androidx.test.runner.AndroidJUnitRunner before (or as the first step of) migrating any test class — the legacy InstrumentationTestRunner does not run JUnit4/Espresso.
• MUST replace getActivity()/setActivityIntent() with ActivityScenario (launch, onActivity { }), not with ActivityTestRule — ActivityTestRule is itself deprecated.
• MUST replace android.test.mock.MockContext/MockResources/MockPackageManager/MockContentResolver subclasses with a real test context where the SUT only reads from it, otherwise a Mockito/MockK mock — never re-derive a new hand-stub from MockContext.
• MUST convert JUnit3 shape (extends TestCase, testFoo(), setUp()/tearDown() overrides, junit.framework.Assert) to JUnit4 (@RunWith(AndroidJUnit4), @Test, @Before/@After, org.junit.Assert/kotlin.test) — do not leave a class half-migrated.
• MUST NOT trust the platform @deprecated Javadoc's literal target (it often names the obsolete android.support.test.* API); migrate to the current AndroidX target in this skill's table.
• PREFERRED: migrate one test class fully per change, with the runner flip landing first; a half-migrated module (some classes on android.test.*, some on AndroidX) is hard to reason about.
• PREFERRED: Google Truth (androidx.test.ext:truth for the Android subjects) over Hamcrest as the MoreAsserts replacement — better failure messages.

Verification

• git grep -n 'import android.test\.' -- '*.java' '*.kt' is empty (or limited to a tracked, justified holdout list).
• No module's testInstrumentationRunner is android.test.InstrumentationTestRunner; all are androidx.test.runner.AndroidJUnitRunner.
• No test class extends ActivityInstrumentationTestCase2 / AndroidTestCase / InstrumentationTestCase / ServiceTestCase / ProviderTestCase2 / junit.framework.TestCase.
• No MoreAsserts. / ViewAsserts. / TouchUtils. references remain.
• No subclass of android.test.mock.MockContext / MockResources / MockPackageManager / MockContentResolver remains.
• Migrated instrumentation tests run green under ./gradlew :module:connectedDebugAndroidTest; migrated host tests under ./gradlew :module:testDebugUnitTest.

References

• developer.android.com/training/testing — AndroidX Test overview; the migration destination for everything in android.test.*.
• developer.android.com/reference/android/test/package-summary — the android.test package reference, every class marked deprecated with its replacement pointer.
• frameworks/base/test-base/src/android/test/AndroidTestCase.java, InstrumentationTestCase.java, UiThreadTest.java, FlakyTest.java (AOSP) — @Deprecated classes whose Javadoc routes to InstrumentationRegistry / androidx.test.annotation.UiThreadTest / androidx.test.filters.FlakyTest.
• frameworks/base/test-runner/src/android/test/ActivityInstrumentationTestCase2.java, ServiceTestCase.java, ProviderTestCase2.java, InstrumentationTestRunner.java, MoreAsserts.java, ViewAsserts.java, TouchUtils.java (AOSP) — the deprecated runner/base classes; Javadocs name ActivityTestRule/ServiceTestRule/AndroidJUnitRunner/Hamcrest/Espresso as replacements.
• frameworks/base/test-mock/src/android/test/mock/MockContext.java, MockPackageManager.java, MockContentResolver.java, MockResources.java, MockCursor.java (AOSP) — the stub-context bases; MockPackageManager's Javadoc explicitly says "use a mocking framework like Mockito".
• Cross-set: ../../../instrumentation/runner/running-instrumented-tests-with-androidjunit4/SKILL.md — the AndroidJUnitRunner / AndroidX Test coordinate matrix to land first.
• Cross-set: ../../../instrumentation/scenarios/launching-activities-with-activityscenario/SKILL.md — ActivityScenario / ActivityScenarioRule, the replacement for ActivityInstrumentationTestCase2.
• Cross-set: ../../../instrumentation/scenarios/launching-fragments-with-fragmentscenario/SKILL.md — FragmentScenario for any home-grown fragment-test bases.
• Cross-set: ../../../instrumentation/espresso/writing-espresso-tests/SKILL.md — Espresso ViewMatchers/ViewActions/ViewAssertions, the replacement for ViewAsserts/TouchUtils.
• Cross-set: ../../../jvm-tests/mocking/mocking-with-mockito/SKILL.md — mocking Context/PackageManager/Resources, the replacement for android.test.mock.*.
• Cross-set: ../../../jvm-tests/robolectric/using-robolectric-correctly/SKILL.md — real Android stubs on the JVM, an alternative to a mock context.
• Cross-set: ../../../kotlin/kotlin-test/writing-tests-with-kotlin-test/SKILL.md — kotlin.test assertions (assertEquals, assertContentEquals, assertFailsWith), one valid replacement for MoreAsserts and junit.framework.Assert.
• Cross-set: ../../../fundamentals/strategies/organizing-test-source-sets/SKILL.md — src/test/ vs src/androidTest/, which the migrated classes need to be sorted into.