code: public function contains($to, TableNode $values)
      {
          $rows = $values->getRowsHash();
  
          foreach ($this->getEmailMessages($to) as $message) {
              foreach ($rows as $field => $value) {
                  if (empty($message[$field])) {
                      throw new \InvalidArgumentException(sprintf('Message does not contain "%s" header.', $field));
                  }
  
                  if (strpos($message[$field], $value) === false) {
                      throw new \RuntimeException(sprintf('Value of "%s" does not contain "%s".', $field, $value));
                  }
              }
          }
      }
docs: @example
  I check that email for "test@example.com" contains:
  | subject | New email letter   |
  | body    | The body of letter |
  I also check that email contains:
  | from    | admin@example.com  |
  
  @param string $to
  Recipient.
  @param TableNode $values
  Left column - is a header key, right - value.
  
  @throws \RuntimeException
  When any message was not sent.
  @throws \InvalidArgumentException
  @throws \RuntimeException
  
  @Given /^(?:|I )check that email for "([^"]*)" contains:$/