@Test
  public void noAddressProvided() {

    assertEquals(
        FormValidation.warning("Empty address list provided").toString(),
        descriptor.doCheckWatcherAddresses("").toString());
  }
  @Test
  public void invalidAddressProvided() {

    assertEquals(
        FormValidation.error("not.an.address does not look like an email address").toString(),
        descriptor.doCheckWatcherAddresses("not.an.address").toString());
  }
  @Test
  public void validAddressProvided() {

    assertEquals(
        FormValidation.ok(),
        descriptor.doCheckWatcherAddresses("an address <*****@*****.**>"));
  }
  @Test
  public void notAnAddressProvided() {

    final String addressCandidate =
        "[email protected], ASDF@#$%^&*(), \"name surname\" <*****@*****.**>";
    final String expectedMessage = "Invalid address provided: Domain contains illegal character";

    assertEquals(
        FormValidation.error(expectedMessage).toString(),
        descriptor.doCheckWatcherAddresses(addressCandidate).toString());
  }