How to create a template for creating a test executable using catch2 with qt and trompeloeil?

I have a project (with main.cpp and some headers. Yes, it is a Catch2 test project as described in this blog). It compiles and runs.

My problem is: This project does nothing useful unless I add some more source files (my test cases). These source files use one header from the project and bring in some other dependencies as well (my library that I want to test).

The simple solution would be to copy this project, add the needed files and we are done.

Is there a better way? Currently with qmake I have the project defined in a catch.pri file. By including this in an project I have everything for the qt and catch2 setup, and only have to define the files with the testcases by modifying the SOURCES-Variable and the dependencies for the code to test.

Mapping this to CMake makes me ask questions:

First: when I include have a line like:

add_executable(tests main.cpp ${SOURCES})

Can I define SOURCES in a later line?

Second and more important: Is it a good idea to do it this way?

Solution

Can I define SOURCES in a later line?

Yes, but not the way you've done it. You can define your executable target tests with a few sources or no sources, but you can always append more sources later using the target_sources command.

add_executable(tests main.cpp)

...

# Later in the CMake file (or in another CMake file added via 'add_subdirectory').
target_sources(tests PRIVATE
    MyTestClass1.cpp
    MyTestClass2.cpp
    ...
)

You can similarly add compilation flags to this tests target later using target_compile_options, and add dependencies to link to tests using target_link_libraries.