Follow the cmake standard of BUILD_TESTING vs KDSingleApplication_TESTS

[TheOneRing]

BUILD_TESTING is the more or less standard flag to enable tests.
Hiding the tests behind KDSingleApplication_TESTS is unintuitive.

[winterz]

Probably this is a WONTFIX. at least for now.
All our projects use namespaced cmake options so if we made this change we'd need to a lot of cmake options in a lot of projects.

[dfaure-kdab]

The good thing about KDSingleApplication_TESTS is that it makes it easy to use KDSingleApplication as a submodule; if you want to build the unittests of the main repo, you don't necessarily want to build those of the 3rdparty libs.

However I can certainly see the benefit of supporting the standard BUILD_TESTING variable when KDSingleApplication is built as a standalone module.

So why don't we do something like this, in KDSingleApplication's own CMakeLists.txt?

if ("${CMAKE_SOURCE_DIR}" STREQUAL "${CMAKE_CURRENT_SOURCE_DIR}" AND BUILD_TESTING)
    set(KDSingleApplication_TESTS ON)
endif()

Untested.

[winterz]

I have no objection to that type of solution.

would be something to add to all our products, eventually. if we want to do that work.