Fake Test Node

What this package provides

When writing an integration test for a node in C++ using GTest, there is quite some boilerplate code that needs to be written to set up a fake node that would publish expected messages on an expected topic and subscribes to messages on some other topic. This is usually implemented as a custom GTest fixture.

This package contains a library that introduces two utility classes that can be used in place of custom fixtures described above to write integration tests for a node:

• autoware::fake_test_node::FakeTestNode - to use as a custom test fixture with TEST_F tests
• autoware::fake_test_node::FakeTestNodeParametrized - to use a custom test fixture with the parametrized TEST_P tests (accepts a template parameter that gets forwarded to testing::TestWithParam<T>)

These fixtures take care of initializing and re-initializing rclcpp as well as of checking that all subscribers and publishers have a match, thus reducing the amount of boilerplate code that the user needs to write.

How to use this library

After including the relevant header the user can use a typedef to use a custom fixture name and use the provided classes as fixtures in TEST_F and TEST_P tests directly.

Example usage

Let's say there is a node NodeUnderTest that requires testing. It just subscribes to std_msgs::msg::Int32 messages and publishes a std_msgs::msg::Bool to indicate that the input is positive. To test such a node the following code can be used utilizing the autoware::fake_test_node::FakeTestNode:

```cpp using FakeNodeFixture = autoware::fake_test_node::FakeTestNode;

/// @test Test that we can use a non-parametrized test. TEST_F(FakeNodeFixture, Test) { Int32 msg{}; msg.data = 15; const auto node = std::make_shared();

Bool::SharedPtr last_received_msg{}; auto fake_odom_publisher = create_publisher("/input_topic"); auto result_odom_subscription = create_subscription("/output_topic", *node, &last_received_msg {last_received_msg = msg;});

const auto dt{std::chrono::milliseconds{100LL}}; const auto max_wait_time{std::chrono::seconds{10LL}}; auto time_passed{std::chrono::milliseconds{0LL}}; while (!last_received_msg) { fake_odom_publisher->publish(msg); rclcpp::spin_some(node); rclcpp::spin_some(get_fake_node()); std::this_thread::sleep_for(dt); time_passed += dt; if (time_passed > max_wait_time) { FAIL() << "Did not receive a message soon enough."; } } EXPECT_TRUE(last_received_msg->data); SUCCEED(); } ```

Here only the TEST_F example is shown but a TEST_P usage is very similar with a little bit more boilerplate to set up all the parameter values, see test_fake_test_node.cpp for an example usage.