Fixed tests running for coverage and added llvm support

CMakeLists.txt

@@ -151,13 +151,24 @@ if("${CMAKE_BUILD_TYPE}" STREQUAL "Coverage")
     message(FATAL_ERROR "gcovr not found, cannot perform coverage.")
   endif()
 
-  set(GCOVR_OPTIONS --object-directory="${PASTIS_BINARY_DIR}" -r "${PASTIS_SOURCE_DIR}/src"  -e "${PASTIS_SOURCE_DIR}/src/experimental" -e "${PASTIS_SOURCE_DIR}/src/main.cpp")
+  if (CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
+    string(REPLACE "clang++" "llvm-cov" LLVM_COV "${CMAKE_CXX_COMPILER}")
+    if(NOT EXISTS "${LLVM_COV}")
+      message(FATAL_ERROR "could not find ${LLVM_COV}, cannot perform coverage (using g++ for coverage is recommended).")
+    endif()
+
+    set(GCOVR_EXTRA "--gcov-executable=${LLVM_COV} gcov")
+  endif()
+
+  set(GCOVR_OPTIONS --object-directory="${PASTIS_BINARY_DIR}" -r "${PASTIS_SOURCE_DIR}/src"  -e "${PASTIS_SOURCE_DIR}/src/experimental" -e "${PASTIS_SOURCE_DIR}/src/main.cpp" ${GCOVR_EXTRA})
+
   add_custom_target(coverage
     ALL
-    # COMMAND ${unit_test_EXECUTABLE}
+    COMMAND ctest -j ${PROCESSOR_COUNT}
     COMMAND ${GCOVR} ${GCOVR_OPTIONS}
     DEPENDS unit_tests pastis
     COMMENT "Running gcovr to build coverage report."
+    USES_TERMINAL
     )
 
   add_custom_target(coverage-report