CTS for DeviceIdleManager (which is @TestApi)

Test: atest cts/tests/tests/batterysaving/src/android/os/cts/deviceidle/DeviceIdleTest.java
Bug: 137763703
Change-Id: Ib5736544788eef69b1b080eb58edaeea89842bf4
diff --git a/tests/tests/batterysaving/src/android/os/cts/deviceidle/DeviceIdleTest.java b/tests/tests/batterysaving/src/android/os/cts/deviceidle/DeviceIdleTest.java
new file mode 100644
index 0000000..61eb49e
--- /dev/null
+++ b/tests/tests/batterysaving/src/android/os/cts/deviceidle/DeviceIdleTest.java
@@ -0,0 +1,37 @@
+/*
+ * Copyright (C) 2019 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.os.cts.deviceidle;
+
+import static org.junit.Assert.assertNotNull;
+
+import android.content.Context;
+
+import androidx.test.filters.SmallTest;
+import androidx.test.platform.app.InstrumentationRegistry;
+import androidx.test.runner.AndroidJUnit4;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+@SmallTest
+@RunWith(AndroidJUnit4.class)
+public class DeviceIdleTest {
+    @Test
+    public void testDeviceIdleManager() {
+        Context context = InstrumentationRegistry.getInstrumentation().getContext();
+        assertNotNull(context.getSystemService(Context.DEVICE_IDLE_CONTROLLER));
+    }
+}