TESTCASE( strpbrk( abcde, "x" ) == NULL );
TESTCASE( strpbrk( abcde, "xyz" ) == NULL );
TESTCASE( strpbrk( abcdx, "x" ) == &abcdx[4] );
TESTCASE( strpbrk( abcde, "x" ) == NULL );
TESTCASE( strpbrk( abcde, "xyz" ) == NULL );
TESTCASE( strpbrk( abcdx, "x" ) == &abcdx[4] );