Test for regexp patterns.

A pattern that gives the expected result produces OK, so that we know it was
actually tried.

STARTTEST
:so small.vim
:" tl is a List of Lists with:
:"    regexp pattern
:"    text to test the pattern on
:"    expected match (optional)
:"    expected submatch 1 (optional)
:"    expected submatch 2 (optional)
:"    etc.
:"  When there is no match use only the first two items.
:let tl = []
:call add(tl, ['b', 'abcdef', 'b'])
:call add(tl, ['bc*', 'abccccdef', 'bcccc'])
:call add(tl, ['bc\{-}', 'abccccdef', 'b'])
:call add(tl, ['bc\{-}\(d\)', 'abccccdef', 'bccccd', 'd'])
:call add(tl, ['x', 'abcdef'])
:"
:for t in tl
:  let l = matchlist(t[1], t[0])
:" check the match itself
:  if len(l) == 0 && len(t) > 2
:    $put ='ERROR: pat: \"' . t[0] . '\", text: \"' . t[1] . '\", did not match, expected: \"' . t[2] . '\"'
:  elseif len(l) > 0 && len(t) == 2
:    $put ='ERROR: pat: \"' . t[0] . '\", text: \"' . t[1] . '\", match: \"' . l[0] . '\", expected no match'
:  elseif len(t) > 2 && l[0] != t[2]
:    $put ='ERROR: pat: \"' . t[0] . '\", text: \"' . t[1] . '\", match: \"' . l[0] . '\", expected: \"' . t[2] . '\"'
:  else
:    $put ='OK'
:  endif
:  if len(l) > 0
:"   check all the nine submatches
:    for i in range(1, 9)
:      if len(t) <= i + 2
:        let e = ''
:      else
:        let e = t[i + 2]
:      endif
:      if l[i] != e
:        $put ='ERROR: pat: \"' . t[0] . '\", text: \"' . t[1] . '\", submatch ' . i . ': \"' . l[i] . '\", expected: \"' . e . '\"'
:      endif
:    endfor
:  endif
:endfor
:/^Results/,$wq! test.out
ENDTEST

Results of test64: