Optimized directory structure

Test/CMakeLists.txt

@@ -0,0 +1,18 @@
+cmake_minimum_required(VERSION 3.16)
+project(Tests)
+
+set(CMAKE_CXX_STANDARD 17)
+
+include_directories(../Src)
+link_directories(../Src/cmake-build-debug)
+
+add_executable(Tests
+        Catch2.h
+        main.cpp
+        Lower.cpp
+        Upper.cpp
+        Replace_Char.cpp
+        Replace_String.cpp
+)
+
+target_link_libraries(Tests StringTools)