Add unit tests for AIDL service

[ Merged from http://go/wvgerrit/150029 ]

Test: m libwvdrmengine_hal_test -j128
Test: m libwvdrmengine_hal_test WV_UNITTESTS_BUILD_TARGET=hidl -j128
Test: adb push $(OUT)/data/nativetest/libwvdrmengine_hal_test /data/nativetest/.
Test: adb shell  LD_LIBRARY_PATH=/vendor/lib64 /data/nativetest/libwvdrmengine_hal_test

Bug: 217247987
Change-Id: Ib4f22c976b8ae6c2983cb611a958ddc3a29aebdb

libwvdrmengine/test/unit/WVCreatePluginFactories_hal_test.cpp

@@ -0,0 +1,28 @@
+//
+// Copyright 2022 Google LLC. All Rights Reserved. This file and proprietary
+// source code may only be used and distributed under the Widevine License
+// Agreement.
+//
+
+#include "WVCreatePluginFactories.h"
+#include "gtest/gtest.h"
+
+namespace wvdrm {
+namespace hardware {
+namespace drm {
+namespace widevine {
+
+using ::wvdrm::hardware::drm::widevine::WVDrmFactory;
+
+TEST(CreatePluginFactoriesTest, CreatesDrmFactory) {
+  std::shared_ptr<WVDrmFactory> drmFactory =
+      ::ndk::SharedRefBase::make<WVDrmFactory>();
+
+  EXPECT_NE((WVDrmFactory *)NULL, drmFactory.get())
+      << "createDrmFactory() returned null";
+}
+
+} // namespace widevine
+} // namespace drm
+} // namespace hardware
+} // namespace wvdrm