TESTCASE( strchr( abccd, 'x' ) == NULL );
TESTCASE( strchr( abccd, 'a' ) == &abccd[0] );
TESTCASE( strchr( abccd, 'd' ) == &abccd[4] );
TESTCASE( strchr( abccd, 'x' ) == NULL );
TESTCASE( strchr( abccd, 'a' ) == &abccd[0] );
TESTCASE( strchr( abccd, 'd' ) == &abccd[4] );