diff --git a/CMakeLists.txt b/CMakeLists.txt
index 00112c6f..cbee492f 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -57,6 +57,13 @@ if(${projectPrefix}IWYU)
     endif()
 endif()
 
+option(${projectPrefix}CLANG_TIDY "Enables clang-tidy" OFF)
+if(${projectPrefix}CLANG_TIDY)
+    message(STATUS "Enabling clang-tidy")
+    set(CMAKE_CXX_CLANG_TIDY clang-tidy)
+    message(STATUS "Enabling clang-tidy - done")
+endif()
+
 #enable_clang_tidy()
 
 # add project code
@@ -72,42 +79,6 @@ add_subdirectory(docs)
 enable_testing()
 add_subdirectory(test)
 
-function(get_target_linked_targets target targets_out)
-    get_target_property(linked_libs ${target} INTERFACE_LINK_LIBRARIES)
-    foreach(linked_lib ${linked_libs})
-        if(NOT linked_lib IN_LIST targets)
-            if(TARGET ${linked_lib})
-                get_target_linked_targets(${linked_lib} child_targets)
-                list(APPEND targets ${linked_lib} ${child_targets})
-            endif()
-        endif()
-    endforeach()
-
-    list(REMOVE_DUPLICATES targets)
-    list(REMOVE_DUPLICATES link_libs)
-    set(${targets_out} ${targets} PARENT_SCOPE)
-endfunction()
-
-function(get_target_sources target paths_out)
-    get_target_linked_targets(${target} targets)
-    list(APPEND targets ${target})
-
-    foreach(t ${targets})
-        get_target_property(sources ${t} SOURCES)
-        if(sources)
-            get_target_property(source_dir ${t} SOURCE_DIR)
-            foreach(f ${sources})
-                file(REAL_PATH "${f}" path BASE_DIRECTORY "${source_dir}")
-                list(APPEND paths "${path}")
-            endforeach()
-        endif()
-    endforeach()
-
-    set(${paths_out} ${paths} PARENT_SCOPE)
-endfunction()
-
 # tests for standalone headers
-include(TestHeaders)
-get_target_sources(mp-units::mp-units sources)
-add_header_test(test_headers HEADERS ${sources})
-target_link_libraries(test_headers PRIVATE mp-units::mp-units)
+include(TestPublicHeaders)
+add_public_header_test(test_headers mp-units::mp-units)
diff --git a/cmake/TestPublicHeaders.cmake b/cmake/TestPublicHeaders.cmake
new file mode 100644
index 00000000..a1d3d4a8
--- /dev/null
+++ b/cmake/TestPublicHeaders.cmake
@@ -0,0 +1,68 @@
+# The MIT License (MIT)
+#
+# Copyright (c) 2018 Mateusz Pusz
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in all
+# copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+
+cmake_minimum_required(VERSION 3.19)
+
+function(get_target_linked_targets target targets_out)
+    get_target_property(linked_libs ${target} INTERFACE_LINK_LIBRARIES)
+    foreach(linked_lib ${linked_libs})
+        if(NOT linked_lib IN_LIST targets)
+            if(TARGET ${linked_lib})
+                get_target_linked_targets(${linked_lib} child_targets)
+                list(APPEND targets ${linked_lib} ${child_targets})
+            endif()
+        endif()
+    endforeach()
+
+    list(REMOVE_DUPLICATES targets)
+    list(REMOVE_DUPLICATES link_libs)
+    set(${targets_out} ${targets} PARENT_SCOPE)
+endfunction()
+
+function(get_target_sources target paths_out)
+    get_target_linked_targets(${target} targets)
+    list(APPEND targets ${target})
+
+    foreach(t ${targets})
+        get_target_property(sources ${t} SOURCES)
+        if(sources)
+            get_target_property(source_dir ${t} SOURCE_DIR)
+            foreach(f ${sources})
+                file(REAL_PATH "${f}" path BASE_DIRECTORY "${source_dir}")
+                file(RELATIVE_PATH path ${CMAKE_CURRENT_LIST_DIR} "${path}")
+                list(APPEND paths "${path}")
+            endforeach()
+        endif()
+    endforeach()
+
+    set(${paths_out} ${paths} PARENT_SCOPE)
+endfunction()
+
+include(TestHeaders)
+
+function(add_public_header_test target test_target)
+    get_target_sources(${test_target} sources)
+    add_header_test(${target} HEADERS ${sources})
+    target_link_libraries(${target} PRIVATE ${test_target})
+    target_include_directories(${target} PRIVATE .)
+endfunction()
+