Linux opencv independent installation : not found in CMake - linux

Question

I am creating an object tracking program which rely on OpenCV. Thus I want to be able to test it with different versions of OpenCV but I have linking errors.
I installed the last version of OpenCV (a69b435c928f422fb5f99c02cf2dcae57dcf820a) in the following folder : /usr/local/opencv/opencv-trunk instead of the usual /usr/local.
Then I followed also the official tutorial to use OpenCV with CMake in Linux, but I had the following "normal" error :
CMake Error at CMakeLists.txt:11 (find_package):
By not providing "FindOpenCV.cmake" in CMAKE_MODULE_PATH this project has asked CMake to find a package configuration file provided by "OpenCV", but CMake did not find one.
Could not find a package configuration file provided by "OpenCV" with any of the following names:
OpenCVConfig.cmake
opencv-config.cmake
Add the installation prefix of "OpenCV" to CMAKE_PREFIX_PATH or set "OpenCV_DIR" to a directory containing one of the above files. If "OpenCV" provides a separate development package or SDK, be sure it has been installed.
-- Configuring incomplete, errors occurred!
So I did what was suggested and added the following line in my CMakeLists.txt :
# Find independently installed OpenCV libraries
set(OpenCV_DIR "/usr/local/opencv/opencv-trunk/share/OpenCV")
This is the complete CMakeLists.txt file :
# Find independently installed OpenCV libraries
set(OpenCV_DIR "/usr/local/opencv/opencv-trunk/share/OpenCV")
cmake_minimum_required(VERSION 2.8)
project( DisplayImage )
add_executable( DisplayImage DisplayImage.cpp )
find_package( OpenCV REQUIRED )
include_directories( ${OpenCV_INCLUDE_DIRS} )
target_link_libraries( DisplayImage ${OpenCV_LIBS} )
Now I have the following error and I don't find how to deal with it.
CMake Error at CMakeLists.txt:12 (find_package):
Found package configuration file:
/usr/local/opencv/opencv-trunk/share/OpenCV/OpenCVConfig.cmake
but it set OpenCV_FOUND to FALSE so package "OpenCV" is considered to be NOT FOUND.
-- Configuring incomplete, errors occurred!
If you have already faced that issue in such context your solutions are welcomed ;)

Answer 1

If you are running IntelliJ or any other IDE, just try re-building CMake cache (or just remove your build directory and run cmake utility again).
I believe this is not the best practice - to set the configuration variable like OpenCV_DIR hard-coded in the CMakeLists.txt. Try setting it manually, as an environment variable to the cmake utility:
OpenCV_DIR=/usr/local/Cellar/opencv3/3.1.0_2/share/OpenCV/ cmake ..
or set your IDE to make this for you: