feat(api): add workaround allowing job resubmission (#241)

As the commit/other information doesn't change when performing a
rebuild, resubmissions will fail with an HTTP 422 error. This adds a
workaround for such cases, appending a random value to the id and
attempting a resubmission with that.

coveralls/api.py

@@ -2,7 +2,9 @@
 import json
 import logging
 import os
+import random
 import re
+import sys
 
 import coverage
 import requests
@@ -202,6 +204,21 @@ def wear(self, dry_run=False):
         verify = not bool(os.environ.get('COVERALLS_SKIP_SSL_VERIFY'))
         response = requests.post(endpoint, files={'json_file': json_string},
                                  verify=verify)
+
+        # check and adjust/resubmit if submission looks like it
+        # failed due to resubmission (non-unique)
+        if response.status_code == 422:
+            self.config['service_job_id'] = '{}-{}'.format(
+                self.config['service_job_id'], random.randint(0, sys.maxsize))
+
+            # ensure create_report uses updated data
+            self._data = None
+
+            print('resubmitting with id {}'.format(
+                self.config['service_job_id']))
+            response = requests.post(endpoint, files={'json_file': self.create_report()},
+                                     verify=verify)
+
         try:
             response.raise_for_status()
             return response.json()