test: add CMAKE_CURRENT_SOURCE_DIR to build interface of includes

Author: aminya

README.md

@@ -90,8 +90,8 @@ add_library(my_header_only_lib INTERFACE)
 target_link_libraries(my_header_only_lib INTERFACE project_options project_warnings) # connect project_options to my_header_only_lib
 
 # Includes
-set(INCLUDE_DIR "./include")
-target_include_directories(my_header_only_lib INTERFACE "$<BUILD_INTERFACE:./${INCLUDE_DIR}>"
+set(INCLUDE_DIR "include")
+target_include_directories(my_header_only_lib INTERFACE "$<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/${INCLUDE_DIR}>"
                                           "$<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>")
 
 # Find dependencies:
@@ -124,8 +124,8 @@ add_library(my_lib "./src/my_lib/lib.cpp")
 target_link_libraries(my_lib INTERFACE project_options project_warnings) # connect project_options to my_lib
 
 # Includes
-set(INCLUDE_DIR "./include")
-target_include_directories(my_lib INTERFACE "$<BUILD_INTERFACE:./${INCLUDE_DIR}>"
+set(INCLUDE_DIR "include")
+target_include_directories(my_lib INTERFACE "$<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/${INCLUDE_DIR}>"
                                             "$<INSTALL_INTERFACE:./${CMAKE_INSTALL_INCLUDEDIR}>")
 
 # Find dependencies:

test/CMakeLists.txt

@@ -67,8 +67,8 @@ add_test(NAME main COMMAND main)
 
 # Header-only library
 add_library(lib INTERFACE)
-set(INCLUDE_DIR "./include")
-target_include_directories(lib INTERFACE "$<BUILD_INTERFACE:./${INCLUDE_DIR}>"
+set(INCLUDE_DIR "include")
+target_include_directories(lib INTERFACE "$<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/${INCLUDE_DIR}>"
                                          "$<INSTALL_INTERFACE:./${CMAKE_INSTALL_INCLUDEDIR}>") # TODO(refactor)
 target_link_libraries(lib INTERFACE project_options project_warnings)
 target_link_system_libraries(
@@ -79,8 +79,8 @@ target_link_system_libraries(
 
 # Library
 add_library(lib2 "./src/mylib2/lib.cpp")
-set(INCLUDE_DIR2 "./include")
-target_include_directories(lib2 INTERFACE "$<BUILD_INTERFACE:./${INCLUDE_DIR2}>"
+set(INCLUDE_DIR2 "include")
+target_include_directories(lib2 INTERFACE "$<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/${INCLUDE_DIR2}>"
                                           "$<INSTALL_INTERFACE:./${CMAKE_INSTALL_INCLUDEDIR}>") # TODO(refactor)
 target_link_libraries(lib2 INTERFACE project_options project_warnings)
 target_link_system_libraries(