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Unit testing#

Unit testing is the first phase of testing and is used to validate units of source code such as classes and functions. Typically, a unit of code is tested by validating its output for various inputs. Unit testing helps ensure that the code behaves as intended and prevents accidental changes of behavior.

Autoware uses the ament_cmake framework to build and run tests. The same framework is also used to analyze the test results.

ament_cmake provides several convenience functions to make it easy to register tests in a CMake-based package and to ensure that JUnit-compatible result files are generated. It currently supports a few different testing frameworks like pytest, gtest, and gmock.

In order to prevent tests running in parallel from interfering with each other when publishing and subscribing to ROS topics, it is recommended to use commands from ament_cmake_ros to run tests in isolation.

See below for an example of using ament_add_ros_isolated_gtest with colcon test. All other tests follow a similar pattern.

Create a unit test with gtest#

In my_cool_pkg/test, create the gtest code file test_my_cool_pkg.cpp:

#include "gtest/gtest.h"
#include "my_cool_pkg/my_cool_pkg.hpp"
TEST(TestMyCoolPkg, TestHello) {
  EXPECT_EQ(my_cool_pkg::print_hello(), 0);

In package.xml, add the following line:


Next add an entry under BUILD_TESTING in the CMakeLists.txt to compile the test source files:


  ament_add_ros_isolated_gtest(test_my_cool_pkg test/test_my_cool_pkg.cpp)
  target_link_libraries(test_my_cool_pkg ${PROJECT_NAME})
  target_include_directories(test_my_cool_pkg PRIVATE src)  # For private headers.

This automatically links the test with the default main function provided by gtest. The code under test is usually in a different CMake target (${PROJECT_NAME} in the example) and its shared object for linking needs to be added. If the test source files include private headers from the src directory, the directory needs to be added to the include path using target_include_directories() function.

To register a new gtest item, wrap the test code with the macro TEST (). TEST () is a predefined macro that helps generate the final test code, and also registers a gtest item to be available for execution. The test case name should be in CamelCase, since gtest inserts an underscore between the fixture name and the class case name when creating the test executable.

gtest/gtest.h also contains predefined macros of gtest like ASSERT_TRUE(condition), ASSERT_FALSE(condition), ASSERT_EQ(val1,val2), ASSERT_STREQ(str1,str2), EXPECT_EQ(), etc. ASSERT_* will abort the test if the condition is not satisfied, while EXPECT_* will mark the test as failed but continue on to the next test condition.


More information about gtest and its features can be found in the gtest repo.

In the demo CMakeLists.txt, ament_add_ros_isolated_gtest is a predefined macro in ament_cmake_ros that helps simplify adding gtest code. Details can be viewed in ament_add_gtest.cmake.

Build test#

By default, all necessary test files (ELF, CTestTestfile.cmake, etc.) are compiled by colcon:

cd ~/workspace/
colcon build --packages-select my_cool_pkg

Test files are generated under ~/workspace/build/my_cool_pkg.

Run test#

To run all tests for a specific package, call:

$ colcon test --packages-select my_cool_pkg

Starting >>> my_cool_pkg
Finished <<< my_cool_pkg [7.80s]

Summary: 1 package finished [9.27s]

The test command output contains a brief report of all the test results.

To get job-wise information of all executed tests, call:

$ colcon test-result --all

build/my_cool_pkg/test_results/my_cool_pkg/copyright.xunit.xml: 8 tests, 0 errors, 0 failures, 0 skipped
build/my_cool_pkg/test_results/my_cool_pkg/cppcheck.xunit.xml: 6 tests, 0 errors, 0 failures, 0 skipped
build/my_cool_pkg/test_results/my_cool_pkg/lint_cmake.xunit.xml: 1 test, 0 errors, 0 failures, 0 skipped
build/my_cool_pkg/test_results/my_cool_pkg/my_cool_pkg_exe_integration_test.xunit.xml: 1 test, 0 errors, 0 failures, 0 skipped
build/my_cool_pkg/test_results/my_cool_pkg/test_my_cool_pkg.gtest.xml: 1 test, 0 errors, 0 failures, 0 skipped
build/my_cool_pkg/test_results/my_cool_pkg/xmllint.xunit.xml: 1 test, 0 errors, 0 failures, 0 skipped

Summary: 18 tests, 0 errors, 0 failures, 0 skipped

Look in the ~/workspace/log/test_<date>/<package_name> directory for all the raw test commands, std_out, and std_err. There is also the ~/workspace/log/latest_*/ directory containing symbolic links to the most recent package-level build and test output.

To print the tests' details while the tests are being run, use the --event-handlers console_cohesion+ option to print the details directly to the console:

$ colcon test --event-handlers console_cohesion+ --packages-select my_cool_pkg

test 1
    Start 1: test_my_cool_pkg

1: Test command: /usr/bin/python3 "-u" "~/workspace/install/share/ament_cmake_test/cmake/" "~/workspace/build/my_cool_pkg/test_results/my_cool_pkg/test_my_cool_pkg.gtest.xml" "--package-name" "my_cool_pkg" "--output-file" "~/workspace/build/my_cool_pkg/ament_cmake_gtest/test_my_cool_pkg.txt" "--command" "~/workspace/build/my_cool_pkg/test_my_cool_pkg" "--gtest_output=xml:~/workspace/build/my_cool_pkg/test_results/my_cool_pkg/test_my_cool_pkg.gtest.xml"
1: Test timeout computed to be: 60
1: -- invoking following command in '~/workspace/src/my_cool_pkg':
1:  - ~/workspace/build/my_cool_pkg/test_my_cool_pkg --gtest_output=xml:~/workspace/build/my_cool_pkg/test_results/my_cool_pkg/test_my_cool_pkg.gtest.xml
1: [==========] Running 1 test from 1 test case.
1: [----------] Global test environment set-up.
1: [----------] 1 test from test_my_cool_pkg
1: [ RUN      ] test_my_cool_pkg.test_hello
1: Hello World
1: [       OK ] test_my_cool_pkg.test_hello (0 ms)
1: [----------] 1 test from test_my_cool_pkg (0 ms total)
1: [----------] Global test environment tear-down
1: [==========] 1 test from 1 test case ran. (0 ms total)
1: [  PASSED  ] 1 test.
1: -- return code 0
1: -- inject classname prefix into gtest result file '~/workspace/build/my_cool_pkg/test_results/my_cool_pkg/test_my_cool_pkg.gtest.xml'
1: -- verify result file '~/workspace/build/my_cool_pkg/test_results/my_cool_pkg/test_my_cool_pkg.gtest.xml'
1/5 Test #1: test_my_cool_pkg ...................   Passed    0.09 sec


100% tests passed, 0 tests failed out of 5

Label Time Summary:
copyright     =   0.49 sec*proc (1 test)
cppcheck      =   0.20 sec*proc (1 test)
gtest         =   0.05 sec*proc (1 test)
lint_cmake    =   0.18 sec*proc (1 test)
linter        =   1.34 sec*proc (4 tests)
xmllint       =   0.47 sec*proc (1 test)

Total Test time (real) =   7.91 sec

Code coverage#

Loosely described, a code coverage metric is a measure of how much of the program code has been exercised (covered) during testing.

In the Autoware repositories, Codecov is used to automatically calculate coverage of any open pull request.

More details about the code coverage metrics can be found in the Codecov documentation.