def test_first_match():
accept = Accept('Content-Type', 'text/html, foo/bar')
assert accept.first_match(['text/html', 'foo/bar']) == 'text/html'
assert accept.first_match(['foo/bar', 'text/html']) == 'foo/bar'
assert accept.first_match(['xxx/xxx', 'text/html']) == 'text/html'
assert accept.first_match(['xxx/xxx']) == 'xxx/xxx'
assert accept.first_match([None, 'text/html']) is None
assert accept.first_match(['text/html', None]) == 'text/html'
assert accept.first_match(['foo/bar', None]) == 'foo/bar'
assert_raises(ValueError, accept.first_match, [])
