Replace regulators StubAction with MockAction

Replace the hand-written StubAction class with a gmock-based MockAction
class.  This is the standard OpenBMC method for stub/mock objects.

Signed-off-by: Shawn McCarney <shawnmm@us.ibm.com>
Change-Id: I5a972032b118a40576829a08020cc2ac675520cc
diff --git a/phosphor-regulators/test/actions/mock_action.hpp b/phosphor-regulators/test/actions/mock_action.hpp
new file mode 100644
index 0000000..2535ef3
--- /dev/null
+++ b/phosphor-regulators/test/actions/mock_action.hpp
@@ -0,0 +1,46 @@
+/**
+ * Copyright © 2019 IBM Corporation
+ *
+ * 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 "action.hpp"
+#include "action_environment.hpp"
+
+#include <gmock/gmock.h>
+
+namespace phosphor
+{
+namespace power
+{
+namespace regulators
+{
+
+class MockAction : public Action
+{
+  public:
+    // Specify which compiler-generated methods we want
+    MockAction() = default;
+    MockAction(const MockAction&) = delete;
+    MockAction(MockAction&&) = delete;
+    MockAction& operator=(const MockAction&) = delete;
+    MockAction& operator=(MockAction&&) = delete;
+    virtual ~MockAction() = default;
+
+    MOCK_METHOD(bool, execute, (ActionEnvironment & environment), (override));
+};
+
+} // namespace regulators
+} // namespace power
+} // namespace phosphor