[TEST] App-template assumes exactly one binary. How do we treat several?

[Irallia]

The app-template assumes exactly one binary, but sometimes we have more. How do we want to deal with it?

In the iGenVar project, for example, we have two binaries. As a result, some CMakeLists do not work correctly.
In seqan/iGenVar#19 we got the Problem, that .../test/CMakeLists.txt with

    # Add the test to its general target (cli or api).
    if (${test_alternative} STREQUAL "CLI_TEST")
        add_dependencies (${target} "${PROJECT_NAME}") # cli test needs the application executable
        target_include_directories(${target} PUBLIC "${SEQAN3_CLONE_DIR}/test/include")
        add_dependencies (cli_test ${target})
    elseif (${test_alternative} STREQUAL "API_TEST")
        add_dependencies (api_test ${target})
    endif ()

the dependencies are not added correctly.

There are 3 ideas to fix this (using the example of iGenVar):

• add_cli_test(detect_breakends_cli_test), this is always done automatically via naming conventions depended on detect_breakends -> update .../test/CMakeLists.txt
• add_cli_test(detect_breakends_cli_test DEPENDS detect_breakends fastq_conversion), i.e. one says which binaries the test needs
• or we add a line in each test, namely: add_dependencies (detect_breakends_cli_test "detect_breakends") and remove this part in iGenVar/test/CMakeLists.txt

[joergi-w]

To me the second version seems the most intuitive one and in this way CMake automatically makes sure that dependent targets are available beforehand.