Add unit testing possibility using googletest on POSIX

cmake/gtest/CMakeLists.txt.in

@@ -0,0 +1,18 @@
+cmake_minimum_required(VERSION 2.8.4)
+
+project(googletest-download NONE)
+
+include(ExternalProject)
+ExternalProject_Add(googletest
+	URL https://github.com/google/googletest/archive/master.zip
+	SOURCE_DIR "${CMAKE_CURRENT_BINARY_DIR}/googletest-src"
+	BINARY_DIR "${CMAKE_CURRENT_BINARY_DIR}/googletest-build"
+	CONFIGURE_COMMAND ""
+	BUILD_COMMAND ""
+	INSTALL_COMMAND ""
+	TEST_COMMAND ""
+	# Wrap download, configure and build steps in a script to log output
+    LOG_DOWNLOAD ON
+    LOG_CONFIGURE ON
+    LOG_BUILD ON
+)

cmake/gtest/gtest.cmake

@@ -0,0 +1,43 @@
+############################################################################
+#
+# Copyright (c) 2019 PX4 Development Team. All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+#
+# 1. Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in
+#    the documentation and/or other materials provided with the
+#    distribution.
+# 3. Neither the name PX4 nor the names of its contributors may be
+#    used to endorse or promote products derived from this software
+#    without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+# FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+# COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+# BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+# OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+# AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+# ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+#
+############################################################################
+
+# Download and unpack googletest at configure time
+configure_file(${CMAKE_CURRENT_LIST_DIR}/CMakeLists.txt.in googletest-download/CMakeLists.txt)
+execute_process(COMMAND ${CMAKE_COMMAND} -G "${CMAKE_GENERATOR}" . RESULT_VARIABLE result1 WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/googletest-download)
+execute_process(COMMAND ${CMAKE_COMMAND} --build . RESULT_VARIABLE result2 WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/googletest-download)
+if(result1 OR result2)
+	message(FATAL_ERROR "Preparing googletest failed: ${result1} ${result2}")
+endif()
+
+# Add googletest, defines gtest and gtest_main targets
+add_subdirectory(${CMAKE_CURRENT_BINARY_DIR}/googletest-src ${CMAKE_CURRENT_BINARY_DIR}/googletest-build EXCLUDE_FROM_ALL)

cmake/gtest/px4_add_gtest.cmake

@@ -0,0 +1,68 @@
+############################################################################
+#
+# Copyright (c) 2019 PX4 Development Team. All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+#
+# 1. Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in
+#    the documentation and/or other materials provided with the
+#    distribution.
+# 3. Neither the name PX4 nor the names of its contributors may be
+#    used to endorse or promote products derived from this software
+#    without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+# FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+# COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+# BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+# OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+# AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+# ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+#
+############################################################################
+
+include(px4_base)
+
+#=============================================================================
+#
+#	px4_add_gtest
+#
+#	Adds a googletest unit test to the unit_test target.
+#
+function(px4_add_gtest)
+	# skip if unit testing is not configured
+	if(unit_testing)
+		# parse source file and library dependencies from arguments
+		px4_parse_function_args(
+			NAME px4_add_gtest
+			ONE_VALUE SRC
+			MULTI_VALUE LINKLIBS
+			REQUIRED SRC
+			ARGN ${ARGN})
+
+		# infer test name from source filname without extension
+		get_filename_component(TESTNAME ${SRC} NAME_WE)
+
+		# build a binary for the unit test
+		add_executable(${TESTNAME} EXCLUDE_FROM_ALL ${SRC})
+
+		# link the libary to test and gtest
+		target_link_libraries(${TESTNAME} ${LINKLIBS} gtest_main)
+
+		# add the test to the ctest plan
+		add_test(NAME ${TESTNAME} COMMAND ${TESTNAME})
+
+		# attach it to the unit test target
+		add_dependencies(unit_test ${TESTNAME})
+	endif()
+endfunction()