Testing with GTest Tutorial (ros2#3359)

Signed-off-by: David V. Lu <[email protected]>

Author: DLu

source/Tutorials/Intermediate/Testing/Cpp.rst

@@ -0,0 +1,65 @@
+.. TestingCpp:
+
+Writing Basic Tests with C++ with GTest
+=======================================
+
+Starting point: we'll assume you have a :ref:`basic ament_cmake package<CreatePkg>` set up already and you want to add some tests to it.
+
+In this tutorial, we'll be using `gtest <https://google.github.io/googletest/primer.html>`__.
+
+Package Setup
+-------------
+
+Source Code
+^^^^^^^^^^^
+We'll start off with our code in a file called ``test/tutorial_test.cpp``
+
+.. code-block:: c++
+
+    #include <gtest/gtest.h>
+
+    TEST(package_name, a_first_test)
+    {
+      ASSERT_EQ(4, 2 + 2);
+    }
+
+    int main(int argc, char** argv)
+    {
+      testing::InitGoogleTest(&argc, argv);
+      return RUN_ALL_TESTS();
+    }
+
+
+package.xml
+^^^^^^^^^^^
+Add the following line to ``package.xml``
+
+.. code-block:: c++
+
+    <test_depend>ament_cmake_gtest</test_depend>
+
+CMakeLists.txt
+^^^^^^^^^^^^^^
+
+.. code-block:: cmake
+
+    if(BUILD_TESTING)
+      find_package(ament_cmake_gtest REQUIRED)
+      ament_add_gtest(${PROJECT_NAME}_tutorial_test test/tutorial_test.cpp)
+      target_include_directories(${PROJECT_NAME}_tutorial_test PUBLIC
+        $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
+        $<INSTALL_INTERFACE:include>
+      )
+      ament_target_dependencies(${PROJECT_NAME}_tutorial_test
+        std_msgs
+      )
+      target_link_libraries(${PROJECT_NAME}_tutorial_test name_of_local_library)
+    endif()
+
+The testing code is wrapped in the ``if/endif`` block to avoid building tests where possible. ``ament_add_gtest`` functions much like ``add_executable`` so you'll need to call ``target_include_directories``, ``ament_target_dependencies`` and ``target_link_libraries`` as you normally would.
+
+
+Running Tests
+-------------
+
+See the :doc:`tutorial on how to run tests from the command line <CLI>` for more information on running the tests and inspecting the test results.

source/Tutorials/Intermediate/Testing/Testing-Main.rst

@@ -39,4 +39,5 @@ Available Tutorials:
    :maxdepth: 1
 
    CLI
+   Cpp
    Python