We don't need to tell arduino to check the current directory for includes. It does that by default

testing/makefiles/testcase.mk

@@ -53,7 +53,7 @@ ${BIN_DIR}/${BIN_FILE}: ${TEST_OBJS}
 # We force sketch recompiliation because otherwise, make won't pick up changes to...anything on the arduino side
 compile-sketch: ${TEST_OBJS}
 	@install -d "${BIN_DIR}" "${LIB_DIR}"
-	env LIBONLY=yes VERBOSE=${VERBOSE}  LOCAL_CFLAGS="'-I$(shell pwd)'" \
+	env LIBONLY=yes VERBOSE=${VERBOSE}  \
 		OUTPUT_PATH="${LIB_DIR}" \
 		$(MAKE) -f ${top_dir}/testing/makefiles/delegate.mk compile
 	$(COMPILER_WRAPPER) $(call _arduino_prop,compiler.cpp.cmd) -o "${BIN_DIR}/${BIN_FILE}" \