ctest not working yet

I open this issue, which traces back to !103 (merged), regarding ctest and gtest.

I finally left the project as this (checkout branch frame-base-tests):

• wolf/src/tests --> here all the gtest files are located

• In wolf/CMakeLists.txt

if(BUILD_TESTS)
    enable_testing()
endif()

• In wolf/src/CMakeLists.txt

if(BUILD_TESTS)    
    MESSAGE("Building tests.")
    add_subdirectory(test)
endif()

• In wolf/src/tests/CMakeLists.txt

# Retrieve googletest from github & compile
add_subdirectory(gtest)
# Include config.h directory at first.
include_directories(${PROJECT_BINARY_DIR}/conf/)
# Include third party directory.
include_directories(${PROJECT_SOURCE_DIR}/third_party/spdlog/include/)
# Include gtest directory.
include_directories(${GTEST_INCLUDE_DIRS})

I compile as usual, and the tests are placed in wolf/bin as usual.

Then, in wolf/build, I call ctest, and this is what I get:

vermicelle:wolf jsola$ ctest
*********************************
No test configuration file found!
*********************************
Usage

  ctest [options]

Help !