added tests

tests/CMakeLists.txt

@@ -0,0 +1,20 @@
+FetchContent_Declare(
+    Catch2
+    GIT_SHALLOW    TRUE
+    GIT_REPOSITORY https://github.com/catchorg/Catch2.git
+    GIT_TAG        v3.5.3
+)
+FetchContent_MakeAvailable(Catch2)
+list(APPEND CMAKE_MODULE_PATH ${Catch2_SOURCE_DIR}/extras)
+
+add_executable(tests test.cpp)
+target_link_libraries(tests PRIVATE Catch2::Catch2WithMain)
+
+set_target_properties(tests PROPERTIES
+        RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}
+        OUTPUT_NAME run_tests
+)
+
+include(CTest)
+include(Catch)
+catch_discover_tests(tests)