test: v4l2_device: Add test suite and initial test

Provide a base class to construct a v4l2_device object for further tests
and an initial test which validates the FD handle can not be leaked.

Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

test/v4l2_device/v4l2_device_test.cpp

@@ -0,0 +1,43 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2019, Google Inc.
+ *
+ * libcamera V4L2 API tests
+ */
+
+#include <iostream>
+#include <sys/stat.h>
+
+#include "v4l2_device_test.h"
+
+using namespace libcamera;
+
+bool exists(const std::string &path)
+{
+	struct stat sb;
+
+	if (stat(path.c_str(), &sb) == 0)
+		return true;
+
+	return false;
+}
+
+int V4L2DeviceTest::init()
+{
+	const std::string device("/dev/video0");
+
+	/* Validate the device node exists. */
+	if (!exists(device)) {
+		std::cout << "No video device available" << std::endl;
+		return TestSkip;
+	}
+
+	dev_ = new V4L2Device(device);
+
+	return dev_->open();
+}
+
+void V4L2DeviceTest::cleanup()
+{
+	delete dev_;
+};