TypeError: string indices must be integers in TransportError (#833)

* Add tests of TransportError

* Fix to work properly even if the error is not structured on TransportError

elasticsearch/exceptions.py

@@ -54,8 +54,11 @@ class TransportError(ElasticsearchException):
     def __str__(self):
         cause = ''
         try:
-            if self.info:
+            if self.info and 'error' in self.info:
+                if isinstance(self.info['error'], dict):
                     cause = ', %r' % self.info['error']['root_cause'][0]['reason']
+                else:
+                    cause = ', %r' % self.info['error']
         except LookupError:
             pass
         return '%s(%s, %r%s)' % (self.__class__.__name__, self.status_code, self.error, cause)

test_elasticsearch/test_exceptions.py

@@ -0,0 +1,23 @@
+from elasticsearch.exceptions import TransportError
+
+from .test_cases import TestCase
+
+
+class TestTransformError(TestCase):
+    def test_transform_error_parse_with_error_reason(self):
+        e = TransportError(500, 'InternalServerError', {
+            'error': {
+                'root_cause': [
+                    {"type": "error", "reason": "error reason"}
+                ]
+            }
+        })
+
+        self.assertEqual(str(e), "TransportError(500, 'InternalServerError', 'error reason')")
+
+    def test_transform_error_parse_with_error_string(self):
+        e = TransportError(500, 'InternalServerError', {
+            'error': 'something error message'
+        })
+
+        self.assertEqual(str(e), "TransportError(500, 'InternalServerError', 'something error message')")