unittest: add virtualwatchdog stub

UNITTESTS/drivers/VirtualWatchdog/VirtualWatchdog.cpp

@@ -0,0 +1,52 @@
+/*
+ * Copyright (c) 2018-2019 Arm Limited and affiliates.
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * 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.
+ */
+#ifdef DEVICE_WATCHDOG
+
+#include "VirtualWatchdog.h"
+
+namespace mbed {
+
+VirtualWatchdog *VirtualWatchdog::_first;
+
+VirtualWatchdog::VirtualWatchdog(uint32_t timeout, const char *const str): _name(str)
+{
+
+}
+
+void VirtualWatchdog::start()
+{
+
+}
+
+void VirtualWatchdog::kick()
+{
+
+}
+
+void VirtualWatchdog::stop()
+{
+
+}
+
+VirtualWatchdog::~VirtualWatchdog()
+{
+
+}
+
+} // namespace mbed
+
+#endif // DEVICE_WATCHDOG