diff --git a/core/src/test/java/google/registry/beam/spec11/Spec11PipelineTest.java b/core/src/test/java/google/registry/beam/spec11/Spec11PipelineTest.java
index d30416519..92f7cf589 100644
--- a/core/src/test/java/google/registry/beam/spec11/Spec11PipelineTest.java
+++ b/core/src/test/java/google/registry/beam/spec11/Spec11PipelineTest.java
@@ -16,6 +16,7 @@ package google.registry.beam.spec11;
 
 import static com.google.common.collect.ImmutableList.toImmutableList;
 import static com.google.common.truth.Truth.assertThat;
+import static com.google.common.truth.Truth.assertWithMessage;
 import static google.registry.model.ImmutableObjectSubject.immutableObjectCorrespondence;
 import static google.registry.persistence.transaction.TransactionManagerFactory.jpaTm;
 
@@ -34,6 +35,7 @@ import google.registry.testing.DatastoreEntityExtension;
 import google.registry.testing.FakeClock;
 import google.registry.util.ResourceUtils;
 import java.io.File;
+import java.lang.reflect.InvocationTargetException;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import org.apache.beam.sdk.coders.KvCoder;
@@ -48,12 +50,8 @@ import org.json.JSONObject;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Order;
 import org.junit.jupiter.api.Test;
-import org.junit.jupiter.api.extension.ExtendWith;
 import org.junit.jupiter.api.extension.RegisterExtension;
 import org.junit.jupiter.api.io.TempDir;
-import org.mockito.junit.jupiter.MockitoExtension;
-import org.mockito.junit.jupiter.MockitoSettings;
-import org.mockito.quality.Strictness;
 
 /**
  * Unit tests for {@link Spec11Pipeline}.
@@ -62,9 +60,8 @@ import org.mockito.quality.Strictness;
  * Therefore we cannot fully test the pipeline but only test the two separate sink IO functions,
  * assuming that date is sourcede correctly the {@code BigQueryIO}.
  */
-@ExtendWith(MockitoExtension.class)
-@MockitoSettings(strictness = Strictness.STRICT_STUBS)
 class Spec11PipelineTest {
+
   private static final String DATE = "2020-01-27";
   private static final String SAFE_BROWSING_API_KEY = "api-key";
   private static final String REPORTING_BUCKET_URL = "reporting_bucket";
@@ -123,6 +120,11 @@ class Spec11PipelineTest {
                     KvCoder.of(
                         SerializableCoder.of(Subdomain.class),
                         SerializableCoder.of(ThreatMatch.class))));
+    assertWithMessage(
+            "Beam pipelines don't run in an App Engine environment, and thus the tests shouldn't be"
+                + " mocking one either")
+        .that(isAppEngine())
+        .isFalse();
   }
 
   @Test
@@ -193,6 +195,25 @@ class Spec11PipelineTest {
         .containsExactlyElementsIn(expectedFileContents.subList(1, expectedFileContents.size()));
   }
 
+  // Adapted from Guava's MoreExecutors (where it is a private method)
+  private static boolean isAppEngine() {
+    if (System.getProperty("com.google.appengine.runtime.environment") == null) {
+      return false;
+    } else {
+      try {
+        return Class.forName("com.google.apphosting.api.ApiProxy")
+                .getMethod("getCurrentEnvironment")
+                .invoke(null)
+            != null;
+      } catch (ClassNotFoundException
+          | InvocationTargetException
+          | IllegalAccessException
+          | NoSuchMethodException e) {
+        return false;
+      }
+    }
+  }
+
   /** Returns the text contents of a file under the beamBucket/results directory. */
   private ImmutableList<String> resultFileContents() throws Exception {
     File resultFile =