diff --git a/tests/cts/net/src/android/net/cts/ConnectivityDiagnosticsManagerTest.java b/tests/cts/net/src/android/net/cts/ConnectivityDiagnosticsManagerTest.java
new file mode 100644
index 0000000..0a80047
--- /dev/null
+++ b/tests/cts/net/src/android/net/cts/ConnectivityDiagnosticsManagerTest.java
@@ -0,0 +1,82 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * 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 android.net.cts;
+
+import static android.net.ConnectivityDiagnosticsManager.ConnectivityDiagnosticsCallback;
+
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.fail;
+
+import android.content.Context;
+import android.net.ConnectivityDiagnosticsManager;
+import android.net.NetworkRequest;
+
+import androidx.test.InstrumentationRegistry;
+import androidx.test.runner.AndroidJUnit4;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import java.util.concurrent.Executor;
+
+@RunWith(AndroidJUnit4.class)
+public class ConnectivityDiagnosticsManagerTest {
+    private static final Executor INLINE_EXECUTOR = x -> x.run();
+    private static final NetworkRequest DEFAULT_REQUEST = new NetworkRequest.Builder().build();
+
+    private Context mContext;
+    private ConnectivityDiagnosticsManager mCdm;
+    private ConnectivityDiagnosticsCallback mCallback;
+
+    @Before
+    public void setUp() throws Exception {
+        mContext = InstrumentationRegistry.getContext();
+        mCdm = mContext.getSystemService(ConnectivityDiagnosticsManager.class);
+
+        mCallback = new ConnectivityDiagnosticsCallback() {};
+    }
+
+    @Test
+    public void testRegisterConnectivityDiagnosticsCallback() {
+        mCdm.registerConnectivityDiagnosticsCallback(DEFAULT_REQUEST, INLINE_EXECUTOR, mCallback);
+    }
+
+    @Test
+    public void testRegisterDuplicateConnectivityDiagnosticsCallback() {
+        mCdm.registerConnectivityDiagnosticsCallback(DEFAULT_REQUEST, INLINE_EXECUTOR, mCallback);
+
+        try {
+            mCdm.registerConnectivityDiagnosticsCallback(
+                    DEFAULT_REQUEST, INLINE_EXECUTOR, mCallback);
+            fail("Registering the same callback twice should throw an IllegalArgumentException");
+        } catch (IllegalArgumentException expected) {
+        }
+    }
+
+    @Test
+    public void testUnregisterConnectivityDiagnosticsCallback() {
+        mCdm.registerConnectivityDiagnosticsCallback(DEFAULT_REQUEST, INLINE_EXECUTOR, mCallback);
+        mCdm.unregisterConnectivityDiagnosticsCallback(mCallback);
+    }
+
+    @Test
+    public void testUnregisterUnknownConnectivityDiagnosticsCallback() {
+        // Expected to silently ignore the unregister() call
+        mCdm.unregisterConnectivityDiagnosticsCallback(mCallback);
+    }
+}