test: use coverage instead of equality to test error payload p.2

We are going to add 'name' payload field for every client error. So
we need to tweak more test to handle this.

Need for tarantool/tarantool#9875

Author: nshy

test/suites/test_dml.py

@@ -385,13 +385,15 @@ def test_15_extra_error_info_stacked(self):
                 error(e2)
             """)
         except DatabaseError as exc:
+            expected_fields = {}
             self.assertEqual(exc.extra_info.type, 'ClientError')
             self.assertTrue(isinstance(exc.extra_info.file, str))
             self.assertEqual(exc.extra_info.line, 3)
             self.assertEqual(exc.extra_info.message, "Timeout exceeded")
             self.assertEqual(exc.extra_info.errno, 0)
             self.assertEqual(exc.extra_info.errcode, 78)
-            self.assertEqual(exc.extra_info.fields, None)
+            self.assertGreaterEqual(exc.extra_info.fields.items(),
+                                    expected_fields.items())
             self.assertNotEqual(exc.extra_info.prev, None)
             prev = exc.extra_info.prev
             self.assertEqual(prev.type, 'ClientError')
@@ -400,7 +402,8 @@ def test_15_extra_error_info_stacked(self):
             self.assertEqual(prev.message, "Unknown error")
             self.assertEqual(prev.errno, 0)
             self.assertEqual(prev.errcode, 0)
-            self.assertEqual(prev.fields, None)
+            self.assertGreaterEqual(prev.fields.items(),
+                                    expected_fields.items())
         else:
             self.fail('Expected error')
 

test/suites/test_error_ext.py

@@ -327,11 +327,11 @@ def test_tarantool_decode(self):
                     self.assertEqual(err.message, expected_err.message)
                     self.assertEqual(err.errno, expected_err.errno)
                     self.assertEqual(err.errcode, expected_err.errcode)
-                    if expected_err.fields is not None:
-                        self.assertGreaterEqual(err.fields.items(),
-                                                expected_err.fields.items())
-                    else:
-                        self.assertEqual(err.fields, None)
+                    expected_fields = expected_err.fields
+                    if expected_fields is None:
+                        expected_fields = {}
+                    self.assertGreaterEqual(err.fields.items(),
+                                            expected_fields.items())
 
                     err = err.prev
                     expected_err = expected_err.prev