Fixed _error_checker in rest client

Restclient's method '_error_checker' for response codes 500 and 501 gets key
error exception when 'resp_body' is a string and passes conditions for
containing of keys.
Also added fix to rarely raised Exceptions after separation main and base
exceptions for two modules.

Closes-Bug: #1280767
Closes-Bug: #1289190
Partially-implements: bp unit-tests
Change-Id: I4b909d008940f8a96efc922daac64a086819c78a
diff --git a/tempest/common/rest_client.py b/tempest/common/rest_client.py
index 66b6fe7..36ddb40 100644
--- a/tempest/common/rest_client.py
+++ b/tempest/common/rest_client.py
@@ -409,7 +409,7 @@
         elif ctype.lower() in TXT_ENC:
             parse_resp = False
         else:
-            raise exceptions.RestClientException(str(resp.status))
+            raise exceptions.InvalidContentType(str(resp.status))
 
         if resp.status == 401 or resp.status == 403:
             raise exceptions.Unauthorized()
@@ -451,25 +451,26 @@
                     # exception.
                     raise exceptions.InvalidHTTPResponseBody(message)
                 else:
-                    # I'm seeing both computeFault
-                    # and cloudServersFault come back.
-                    # Will file a bug to fix, but leave as is for now.
-                    if 'cloudServersFault' in resp_body:
-                        message = resp_body['cloudServersFault']['message']
-                    elif 'computeFault' in resp_body:
-                        message = resp_body['computeFault']['message']
-                    elif 'error' in resp_body:  # Keystone errors
-                        message = resp_body['error']['message']
-                        raise exceptions.IdentityError(message)
-                    elif 'message' in resp_body:
-                        message = resp_body['message']
+                    if isinstance(resp_body, dict):
+                        # I'm seeing both computeFault
+                        # and cloudServersFault come back.
+                        # Will file a bug to fix, but leave as is for now.
+                        if 'cloudServersFault' in resp_body:
+                            message = resp_body['cloudServersFault']['message']
+                        elif 'computeFault' in resp_body:
+                            message = resp_body['computeFault']['message']
+                        elif 'error' in resp_body:  # Keystone errors
+                            message = resp_body['error']['message']
+                            raise exceptions.IdentityError(message)
+                        elif 'message' in resp_body:
+                            message = resp_body['message']
+                    else:
+                        message = resp_body
 
             raise exceptions.ServerFault(message)
 
         if resp.status >= 400:
-            if parse_resp:
-                resp_body = self._parse_resp(resp_body)
-            raise exceptions.RestClientException(str(resp.status))
+            raise exceptions.UnexpectedResponseCode(str(resp.status))
 
     def is_absolute_limit(self, resp, resp_body):
         if (not isinstance(resp_body, collections.Mapping) or
diff --git a/tempest/exceptions/__init__.py b/tempest/exceptions/__init__.py
index c95f94f..06dee71 100644
--- a/tempest/exceptions/__init__.py
+++ b/tempest/exceptions/__init__.py
@@ -146,3 +146,11 @@
 
 class InvalidHTTPResponseBody(base.RestClientException):
     message = "HTTP response body is invalid json or xml"
+
+
+class InvalidContentType(base.RestClientException):
+    message = "Invalid content type provided"
+
+
+class UnexpectedResponseCode(base.RestClientException):
+    message = "Unexpected response code received"
diff --git a/tempest/tests/test_rest_client.py b/tempest/tests/test_rest_client.py
index 9f07972..827b5c9 100644
--- a/tempest/tests/test_rest_client.py
+++ b/tempest/tests/test_rest_client.py
@@ -230,3 +230,114 @@
         data = {"one_top_key": "not_list_or_dict_value"}
         body = self.rest_client._parse_resp(json.dumps(data))
         self.assertEqual(data, body)
+
+
+class TestRestClientErrorCheckerJSON(base.TestCase):
+    c_type = "application/json"
+
+    def set_data(self, r_code, enc=None, r_body=None):
+        if enc is None:
+            enc = self.c_type
+        resp_dict = {'status': r_code, 'content-type': enc}
+        resp = httplib2.Response(resp_dict)
+        data = {
+            "method": "fake_method",
+            "url": "fake_url",
+            "headers": "fake_headers",
+            "body": "fake_body",
+            "resp": resp,
+            "resp_body": '{"resp_body": "fake_resp_body"}',
+        }
+        if r_body is not None:
+            data.update({"resp_body": r_body})
+        return data
+
+    def setUp(self):
+        super(TestRestClientErrorCheckerJSON, self).setUp()
+        self.stubs.Set(config, 'TempestConfigPrivate', fake_config.FakeConfig)
+        self.rest_client = rest_client.RestClient(
+            fake_auth_provider.FakeAuthProvider())
+
+    def test_response_less_than_400(self):
+        self.rest_client._error_checker(**self.set_data("399"))
+
+    def test_response_400(self):
+        self.assertRaises(exceptions.BadRequest,
+                          self.rest_client._error_checker,
+                          **self.set_data("400"))
+
+    def test_response_401(self):
+        self.assertRaises(exceptions.Unauthorized,
+                          self.rest_client._error_checker,
+                          **self.set_data("401"))
+
+    def test_response_403(self):
+        self.assertRaises(exceptions.Unauthorized,
+                          self.rest_client._error_checker,
+                          **self.set_data("403"))
+
+    def test_response_404(self):
+        self.assertRaises(exceptions.NotFound,
+                          self.rest_client._error_checker,
+                          **self.set_data("404"))
+
+    def test_response_409(self):
+        self.assertRaises(exceptions.Conflict,
+                          self.rest_client._error_checker,
+                          **self.set_data("409"))
+
+    def test_response_413(self):
+        self.assertRaises(exceptions.OverLimit,
+                          self.rest_client._error_checker,
+                          **self.set_data("413"))
+
+    def test_response_422(self):
+        self.assertRaises(exceptions.UnprocessableEntity,
+                          self.rest_client._error_checker,
+                          **self.set_data("422"))
+
+    def test_response_500_with_text(self):
+        # _parse_resp is expected to return 'str'
+        self.assertRaises(exceptions.ServerFault,
+                          self.rest_client._error_checker,
+                          **self.set_data("500"))
+
+    def test_response_501_with_text(self):
+        self.assertRaises(exceptions.ServerFault,
+                          self.rest_client._error_checker,
+                          **self.set_data("501"))
+
+    def test_response_500_with_dict(self):
+        r_body = '{"resp_body": {"err": "fake_resp_body"}}'
+        self.assertRaises(exceptions.ServerFault,
+                          self.rest_client._error_checker,
+                          **self.set_data("500", r_body=r_body))
+
+    def test_response_501_with_dict(self):
+        r_body = '{"resp_body": {"err": "fake_resp_body"}}'
+        self.assertRaises(exceptions.ServerFault,
+                          self.rest_client._error_checker,
+                          **self.set_data("501", r_body=r_body))
+
+    def test_response_bigger_than_400(self):
+        # Any response code, that bigger than 400, and not in
+        # (401, 403, 404, 409, 413, 422, 500, 501)
+        self.assertRaises(exceptions.UnexpectedResponseCode,
+                          self.rest_client._error_checker,
+                          **self.set_data("402"))
+
+
+class TestRestClientErrorCheckerXML(TestRestClientErrorCheckerJSON):
+    c_type = "application/xml"
+
+
+class TestRestClientErrorCheckerTEXT(TestRestClientErrorCheckerJSON):
+    c_type = "text/plain"
+
+    def test_fake_content_type(self):
+        # This test is required only in one exemplar
+        # Any response code, that bigger than 400, and not in
+        # (401, 403, 404, 409, 413, 422, 500, 501)
+        self.assertRaises(exceptions.InvalidContentType,
+                          self.rest_client._error_checker,
+                          **self.set_data("405", enc="fake_enc"))