METRON-1299 In MetronError tests, don't test for HostName if getHostName wouldn't work

[ottobackwards]

MetronError ignores exceptions from InetAddress.getLocalHost().getHostName() and leaves the field unset.

The unit test however assumes it would be set, and someone has logged a jira on this, since it makes the build fail.

Changed the test so that it only verifies the hostName if it would have worked.

Testing

• Code review
• Tests Pass

no non-test changes in pr

 private void addHostname(JSONObject errorMessage) {
    try {
      errorMessage.put(ErrorFields.HOSTNAME.getName(), InetAddress.getLocalHost().getHostName());
    } catch (UnknownHostException ex) {
      // Leave the hostname field off if it cannot be found
    }
  }

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• Is there a JIRA ticket associated with this PR? If not one needs to be created at Metron Jira.
• Does your PR title start with METRON-XXXX where XXXX is the JIRA number you are trying to resolve? Pay particular attention to the hyphen "-" character.
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[cestella]

So, in the instance where this happens, is hostName is null or is it that there's an Exception thrown? If it's null, can't we do a:

if(hostName == null) {
  LOG.warn("Unable to resolve local hostname, skipping validation."
}
else {
  assertTrue(((String) errorJSON.get(Constants.ErrorFields.HOSTNAME.getName())).length() > 0);
  assertEquals(hostName, (String) errorJSON.get(Constants.ErrorFields.HOSTNAME.getName()));
}

I ask because I worry about extraneous other exceptions cropping up and us ignoring them. It's a very small nit, let me know what you think. :)

[merrimanr]

+1 pending @cestella's approval. Thanks @ottobackwards.

[justinleet]

@cestella Bump

[cestella]

+1, sorry!