diff --git a/dlib/test/CMakeLists.txt b/dlib/test/CMakeLists.txt
index 49e44fe2d4..64b7de1078 100644
--- a/dlib/test/CMakeLists.txt
+++ b/dlib/test/CMakeLists.txt
@@ -9,9 +9,13 @@ cmake_minimum_required(VERSION 3.10.0)
 set (target_name dtest)
 PROJECT(${target_name})
 
+option(Werror "Error on warnings" ON)
+
 # compile the dlib/all/source.cpp file into its own object just to make sure it compiles
 set(DLIB_TEST_COMPILE_ALL_SOURCE_CPP ON)
 
+
+
 add_subdirectory(.. dlib_build)
 
 add_executable(${target_name} main.cpp tester.cpp
@@ -169,8 +173,13 @@ get_filename_component(DLIB_FFMPEG_DATA ${CMAKE_SOURCE_DIR}/ffmpeg_data/details.
 target_compile_definitions(${target_name} PRIVATE DLIB_FFMPEG_DATA="${DLIB_FFMPEG_DATA}")
 
 if (CMAKE_COMPILER_IS_GNUCXX)
-   # Turn on all warnings, and treat them as errors.
-   add_compile_options(-W -Wall -Wextra -Wpedantic -Werror)
+   # Turn on all warnings, and treat them as errors by default
+   add_compile_options(-W -Wall -Wextra -Wpedantic)
+   if (Werror)
+       add_compile_options(-Werror)
+   endif()
+
+   add_compile_options(-fdiagnostics-color=always)
    # I don't care about unused testing functions though.  I like to keep them
    # around.  Don't warn about it.
    add_compile_options(-Wno-unused-function)
@@ -204,11 +213,16 @@ if (CMAKE_COMPILER_IS_GNUCXX)
    endif()
 
 elseif (MSVC)
-   # Treat warnings as errors.
-   add_compile_options(/WX)
+   if (Werror)
+      # Treat warnings as errors.
+      add_compile_options(/WX)
+   endif()
 else() # basically Clang
    # Treat warnings as errors, but do not turn on all warnings.
-   add_compile_options(-W -Werror)
+   add_compile_options(-W)
+   if (Werror)
+      add_compile_options(-Werror)
+   endif()
    # This is for the comment in face_detection_ex.cpp that says "faces/*.jpg"
    add_compile_options(-Wno-comment)