Unit test.

Author: kannanjgithub

core/src/main/java/io/grpc/internal/CallExecutors.java

@@ -43,13 +43,4 @@ static Executor safeguard(Executor executor) {
     }
     return new SerializingExecutor(executor);
   }
-
-  /**
-   * Returns true if the executor is safeguarded (e.g. a {@link SerializingExecutor} or
-   * {@link SerializeReentrantCallsDirectExecutor}).
-   */
-  static boolean isSafeguarded(Executor executor) {
-    return executor instanceof SerializingExecutor
-        || executor instanceof SerializeReentrantCallsDirectExecutor;
-  }
 }

core/src/test/java/io/grpc/internal/CallExecutorsTest.java

@@ -0,0 +1,68 @@
+/*
+ * Copyright 2026 The gRPC Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.grpc.internal;
+
+import static com.google.common.util.concurrent.MoreExecutors.directExecutor;
+import static org.junit.Assert.assertSame;
+import static org.junit.Assert.assertTrue;
+
+import java.util.concurrent.Executor;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+
+@RunWith(JUnit4.class)
+public class CallExecutorsTest {
+
+  @Test
+  public void safeguard_alreadySerializing_returnsSameInstance() {
+    Executor raw = command -> command.run();
+    SerializingExecutor serializing = new SerializingExecutor(raw);
+    assertSame(serializing, CallExecutors.safeguard(serializing));
+  }
+
+  @Test
+  public void safeguard_alreadySerializeReentrantCallsDirect_returnsSameInstance() {
+    SerializeReentrantCallsDirectExecutor direct = new SerializeReentrantCallsDirectExecutor();
+    assertSame(direct, CallExecutors.safeguard(direct));
+  }
+
+  @Test
+  public void safeguard_directExecutor_returnsSerializeReentrantCallsDirect() {
+    Executor safeguarded = CallExecutors.safeguard(directExecutor());
+    assertTrue(safeguarded instanceof SerializeReentrantCallsDirectExecutor);
+  }
+
+  @Test
+  public void safeguard_otherExecutor_returnsSerializing() {
+    Executor raw = command -> command.run();
+    Executor safeguarded = CallExecutors.safeguard(raw);
+    assertTrue(safeguarded instanceof SerializingExecutor);
+  }
+
+  @Test
+  public void safeguard_idempotent() {
+    Executor raw = command -> command.run();
+    Executor first = CallExecutors.safeguard(raw);
+    Executor second = CallExecutors.safeguard(first);
+    assertSame(first, second);
+
+    Executor firstDirect = CallExecutors.safeguard(directExecutor());
+    Executor secondDirect = CallExecutors.safeguard(firstDirect);
+    assertSame(firstDirect, secondDirect);
+  }
+}