RFC: Make ECMAddTests respect BUILD_TESTING

Summary:
Use-case: Make building unit tests optional, by just following the CMake
BUILD_TESTING option.

The usual approach to conditionally build tests is to do:
```
if (BUILD_TESTING)
    add_executable(TestOne TestOne.cpp)
    target_link_libraries(TestOne my_library)
endif()
```

or:

```
if (BUILD_TESTING)
    add_subdirectory(tests)
endif()
```

This patch just turns all calls to ecm_add_test(...) into no-ops if
BUILD_TESTING=OFF.

See:
  https://cmake.org/cmake/help/v3.6/module/CTest.html

Reviewers: vkrause

Reviewed By: vkrause

Subscribers: kossebau, vkrause, elvisangelaccio, asturmlechner, apol, #frameworks, #build_system

Tags: #frameworks, #build_system

Differential Revision: https://phabricator.kde.org/D7187

0 files changed, 0 insertions, 0 deletions