diff --git a/library/core/src/test/java/com/google/android/exoplayer2/mediacodec/DedicatedThreadAsyncMediaCodecAdapterTest.java b/library/core/src/test/java/com/google/android/exoplayer2/mediacodec/DedicatedThreadAsyncMediaCodecAdapterTest.java
index 01fcdb0711..2ce2e5084a 100644
--- a/library/core/src/test/java/com/google/android/exoplayer2/mediacodec/DedicatedThreadAsyncMediaCodecAdapterTest.java
+++ b/library/core/src/test/java/com/google/android/exoplayer2/mediacodec/DedicatedThreadAsyncMediaCodecAdapterTest.java
@@ -290,11 +290,14 @@ public class DedicatedThreadAsyncMediaCodecAdapterTest {
     AtomicInteger onCodecStartCount = new AtomicInteger(0);
     adapter.setCodecStartRunnable(() -> onCodecStartCount.incrementAndGet());
     adapter.start();
+    // Grab reference to Looper before shutting down the adapter otherwise handlerThread.getLooper()
+    // might return null.
+    Looper looper = handlerThread.getLooper();
     adapter.flush();
     adapter.shutdown();
 
     // Wait until all tasks have been handled.
-    Shadows.shadowOf(handlerThread.getLooper()).idle();
+    Shadows.shadowOf(looper).idle();
     // Only adapter.start() calls onCodecStart.
     assertThat(onCodecStartCount.get()).isEqualTo(1);
   }
diff --git a/library/core/src/test/java/com/google/android/exoplayer2/mediacodec/MultiLockAsyncMediaCodecAdapterTest.java b/library/core/src/test/java/com/google/android/exoplayer2/mediacodec/MultiLockAsyncMediaCodecAdapterTest.java
index bc9baab577..1232d8bf3e 100644
--- a/library/core/src/test/java/com/google/android/exoplayer2/mediacodec/MultiLockAsyncMediaCodecAdapterTest.java
+++ b/library/core/src/test/java/com/google/android/exoplayer2/mediacodec/MultiLockAsyncMediaCodecAdapterTest.java
@@ -290,10 +290,13 @@ public class MultiLockAsyncMediaCodecAdapterTest {
     AtomicInteger codecStartCalls = new AtomicInteger(0);
     adapter.setCodecStartRunnable(() -> codecStartCalls.incrementAndGet());
     adapter.start();
+    // Grab reference to Looper before shutting down the adapter otherwise handlerThread.getLooper()
+    // might return null.
+    Looper looper = handlerThread.getLooper();
     adapter.flush();
     adapter.shutdown();
 
-    Shadows.shadowOf(handlerThread.getLooper()).idle();
+    Shadows.shadowOf(looper).idle();
     // Only adapter.start() called codec#start()
     assertThat(codecStartCalls.get()).isEqualTo(1);
   }