Custom tests are enabled by creating two (2) or three (3) different files in the custom_tests directory.
The first file to create is the Description File. The Description File is a file with a .md extension that resides in the descrs directory. The purpose of this file is to identify the name of the test (everything before the .md extension) and provide a place to document the purpose of the test.
The second file to create is the Source File. The Source file should reside in the srcs directory and have a name that matches its Description File (with the .cc extension rather than the .md extension).
The final file is optional. The Input File resides in the data directory and should have the same name as the other two (2) files but with an .input extension rather than .cc or .md for the Source and Description File respectively. If present, the contents of this file will be given to the executed custom test over standard input.
The Source Files for a custom test are compiled using C++20 and are saved as an executable named according to the name of the test in the CMake build directory.
All successful tests should return 0. All failing tests should return something other than 0.
To reduce the boilerplate needed to write custom tests, there is a custom test library with several helpful functions. These functions are documented in the library's header file (custom_tests/srcs/ubpf_custom_test_support.h).
After describing the test‘s purpose in a Markdown syntax in a file named, say, test_example.md and stored in the descrs directory, you can write the test’s Source Code (in C++20) and give it the name test_example.cc in the srcs directory. If the test needs input, you can save that input in the tests Input File (test_input.input) in the data directory.
Because all the files are present, this test will be run when the CTest target is invoked. Because there the optional test_input.input file is present, the contents of that file will be given to the executable via standard input.