The two key commands here are enable_testing(), which enables testing for this directory and all subfolders within it (in this case, the entire project, since we place it in the main CMakeLists.txt), and add_test(), which defines a new test and sets the test name and the command to run; an example is as follows:
add_test( NAME cpp_test COMMAND $<TARGET_FILE:cpp_test> )
In the preceding example, we employed a generator expression: $<TARGET_FILE:cpp_test>. Generator expressions are expressions that are evaluated at build system generation time. We will return to generator expressions in more detail in Chapter 5, Configure-time and Build-time Operations, Recipe 9, Fine-tuning configuration and compilation with generator expressions ...
