audiopolicy: Add unit tests build target

This change adds audiopolicy_tests target for running
unit tests of AudioPolicyManager class.

AudioPolicyManager class is modified to allow
finer control over the configuration loading.

Test: audiopolicy_tests
Change-Id: Icf0cd7ff5b3b8b827b4f6909ff2c138ac2a2b82e
diff --git a/services/audiopolicy/tests/AudioPolicyTestManager.h b/services/audiopolicy/tests/AudioPolicyTestManager.h
new file mode 100644
index 0000000..fe543a6
--- /dev/null
+++ b/services/audiopolicy/tests/AudioPolicyTestManager.h
@@ -0,0 +1,30 @@
+/*
+ * Copyright (C) 2017 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.
+ */
+#pragma once
+
+#include "managerdefault/AudioPolicyManager.h"
+
+namespace android {
+
+class AudioPolicyTestManager : public AudioPolicyManager {
+  public:
+    explicit AudioPolicyTestManager(AudioPolicyClientInterface *clientInterface)
+            : AudioPolicyManager(clientInterface, true /*forTesting*/) { }
+    using AudioPolicyManager::getConfig;
+    using AudioPolicyManager::initialize;
+};
+
+}  // namespace android