Give tests access to IOR if available

CMakeLists.txt

@@ -374,6 +374,14 @@ endif()
 
 if(CMAKE_PROJECT_NAME STREQUAL HERMES AND BUILD_TESTING)
   find_package(Catch2 REQUIRED)
+  find_program(IOR_EXE ior)
+  if(IOR_EXE)
+    message(STATUS "Found ior at ${IOR_EXE}")
+    set(HERMES_HAVE_IOR "YES")
+  else()
+    message(WARNING "Couldn't find the 'ior' executable. Some tests will be skipped.")
+    set(HERMES_HAVE_IOR "NO")
+  endif()
   enable_testing()
   add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/test)
 endif()