1 files changed, 191 insertions, 0 deletions
diff --git a/robolectric/src/test/java/org/robolectric/shadows/ShadowLooperResetterTest.java b/robolectric/src/test/java/org/robolectric/shadows/ShadowLooperResetterTest.java
new file mode 100644
index 000000000..92e1643c5
--- /dev/null
+++ b/robolectric/src/test/java/org/robolectric/shadows/ShadowLooperResetterTest.java
@@ -0,0 +1,191 @@
+package org.robolectric.shadows;
+
+import static android.os.Looper.getMainLooper;
+import static com.google.common.base.Preconditions.checkNotNull;
+import static com.google.common.base.Preconditions.checkState;
+import static com.google.common.truth.Truth.assertThat;
+import static org.robolectric.Shadows.shadowOf;
+
+import android.os.Handler;
+import android.os.HandlerThread;
+import java.time.Duration;
+import java.util.concurrent.atomic.AtomicBoolean;
+import org.junit.AfterClass;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runner.Runner;
+import org.junit.runner.notification.Failure;
+import org.junit.runner.notification.RunListener;
+import org.junit.runner.notification.RunNotifier;
+import org.junit.runners.JUnit4;
+import org.junit.runners.model.InitializationError;
+import org.robolectric.RobolectricTestRunner;
+
+/** A specialized test for verifying that looper state is cleared properly between tests. */
+@RunWith(JUnit4.class)
+public class ShadowLooperResetterTest {
+  private final RunNotifier runNotifier = new RunNotifier();
+
+  @Before
+  public void setup() {
+    runNotifier.addListener(
+        new RunListener() {
+          @Override
+          public void testFailure(Failure failure) throws Exception {
+            throw new AssertionError("Unexpected test failure: " + failure, failure.getException());
+          }
+        });
+  }
+
+  /**
+   * Basic test class that interacts with Looper in two different tests, to ensure Looper remains
+   * functional after reset.
+   */
+  public static class BasicLooperTest {
+
+    private void doPostToLooperTest() {
+      checkNotNull(getMainLooper());
+
+      AtomicBoolean didRun = new AtomicBoolean(false);
+      new Handler(getMainLooper()).post(() -> didRun.set(true));
+
+      assertThat(didRun.get()).isFalse();
+      shadowOf(getMainLooper()).idle();
+      assertThat(didRun.get()).isTrue();
+    }
+
+    @Test
+    public void postToLooperTest() {
+      doPostToLooperTest();
+    }
+
+    @Test
+    public void anotherPostToLooperTest() {
+      doPostToLooperTest();
+    }
+  }
+
+  @Test
+  public void basicPostAndRun() throws InitializationError {
+    Runner runner = new RobolectricTestRunner(BasicLooperTest.class);
+
+    // run and assert no failures
+    runner.run(runNotifier);
+  }
+
+  /** Test that leaves an unexecuted runnable on Looper and verifies it is removed between tests. */
+  public static class PendingLooperTest {
+
+    private void doPostToLooperTest() {
+      checkState(shadowOf(getMainLooper()).isIdle());
+
+      AtomicBoolean didRun = new AtomicBoolean(false);
+      new Handler(getMainLooper()).post(() -> didRun.set(true));
+
+      assertThat(didRun.get()).isFalse();
+      assertThat(shadowOf(getMainLooper()).isIdle()).isFalse();
+    }
+
+    @Test
+    public void postToLooperTest() {
+      doPostToLooperTest();
+    }
+
+    @Test
+    public void anotherPostToLooperTest() {
+      doPostToLooperTest();
+    }
+  }
+
+  @Test
+  public void pendingTasksClearer() throws InitializationError {
+    Runner runner = new RobolectricTestRunner(PendingLooperTest.class);
+
+    // run and assert no failures
+    runner.run(runNotifier);
+  }
+
+  /** Test that uses delayed tasks */
+  public static class DelayedTaskTest {
+
+    private void doDelayedPostToLooperTest() {
+      checkState(shadowOf(getMainLooper()).isIdle());
+
+      AtomicBoolean didRun = new AtomicBoolean(false);
+      new Handler(getMainLooper()).postDelayed(() -> didRun.set(true), 100);
+      shadowOf(getMainLooper()).idle();
+      assertThat(didRun.get()).isFalse();
+      shadowOf(getMainLooper()).idleFor(Duration.ofMillis(100));
+      assertThat(didRun.get()).isTrue();
+    }
+
+    @Test
+    public void postToLooperTest() {
+      doDelayedPostToLooperTest();
+    }
+
+    @Test
+    public void anotherPostToLooperTest() {
+      doDelayedPostToLooperTest();
+    }
+  }
+
+  @Test
+  public void delayedTask() throws InitializationError {
+    Runner runner = new RobolectricTestRunner(DelayedTaskTest.class);
+
+    // run and assert no failures
+    runner.run(runNotifier);
+  }
+
+  /** Test that uses delayed tasks on a running looper */
+  public static class DelayedTaskRunningLooperTest {
+
+    // use a static thread so both tests share the same looper
+    static HandlerThread handlerThread;
+
+    @Before
+    public void init() {
+      if (handlerThread == null) {
+        handlerThread = new HandlerThread("DelayedTaskRunningLooperTest");
+        handlerThread.start();
+      }
+    }
+
+    @AfterClass
+    public static void shutDown() throws InterruptedException {
+      handlerThread.quit();
+      handlerThread.join();
+    }
+
+    private void doDelayedPostToLooperTest() {
+      checkNotNull(handlerThread.getLooper());
+
+      AtomicBoolean didRun = new AtomicBoolean(false);
+      new Handler(handlerThread.getLooper()).postDelayed(() -> didRun.set(true), 100);
+      shadowOf(handlerThread.getLooper()).idle();
+      assertThat(didRun.get()).isFalse();
+      shadowOf(handlerThread.getLooper()).idleFor(Duration.ofMillis(100));
+      assertThat(didRun.get()).isTrue();
+    }
+
+    @Test
+    public void postToLooperTest() {
+      doDelayedPostToLooperTest();
+    }
+
+    @Test
+    public void anotherPostToLooperTest() {
+      doDelayedPostToLooperTest();
+    }
+  }
+
+  @Test
+  public void delayedTaskRunningLooper() throws InitializationError {
+    Runner runner = new RobolectricTestRunner(DelayedTaskRunningLooperTest.class);
+
+    // run and assert no failures
+    runner.run(runNotifier);
+  }
+}