--- /dev/null
+#include <acheam.h>
+#include <assert.h>
+
+#include <string.h>
+#include <stdio.h>
+
+int
+main(void)
+{
+ // tolowerw()
+ assert(strcmp(tolowerw("eXaMpLe StRiNg"), "example string") == 0);
+
+ // toupperw()
+ assert(strcmp(toupperw("eXaMpLe StRiNg"), "EXAMPLE STRING") == 0);
+
+ printf("All tests passed succesfully!\n");
+ return 0;
+}