INVALID_EMAILS = [
  'invalid@example-com',
  # period can not start local part
  '.invalid@example.com',
  # period can not end local part
  'invalid.@example.com',
  # period can not appear twice consecutively in local part
  'invali..d@example.com',
  # should not allow underscores in domain names
  'invalid@ex_mple.com',
  'invalid@example.com.',
  'invalid@example.com_',
  'invalid@example.com-',
  'invalid-example.com',
  'invalid@example.b#r.com',
  'invalid@example.c',
  'invali d@example.com',
  'invalidexample.com',
  'invalid@example.',
  # from http://tools.ietf.org/html/rfc3696, page 5
  # corrected in http://www.rfc-editor.org/errata_search.php?rfc=3696
  'Fred\ Bloggs_@example.com',
  'Abc\@def+@example.com',
  'Joe.\\Blow@example.com'
]

VALID_EMAILS = [
  'valid@example.com',
  'Valid@test.example.com',
  'valid+valid123@test.example.com',
  'valid_valid123@test.example.com',
  'valid-valid+123@test.example.co.uk',
  'valid-valid+1.23@test.example.com.au',
  'valid@example.co.uk',
  'v@example.com',
  'valid@example.ca',
  'valid_@example.com',
  'valid123.456@example.org',
  'valid123.456@example.travel',
  'valid123.456@example.museum',
  'valid@example.mobi',
  'valid@example.info',
  'valid-@example.com',
  # from RFC 3696, page 6
  'customer/department=shipping@example.com',
  '$A12345@example.com',
  '!def!xyz%abc@example.com',
  '_somename@example.com',
  # apostrophes
  "test'test@example.com",
  # '"Abc\@def"@example.com',
  # from http://www.rfc-editor.org/errata_search.php?rfc=3696
  # '"Fred\ Bloggs"@example.com',
  '"Joe.\\Blow"@example.com'
]