Fix failures due to CheckMessage.hint being optional

Author: adamchainz

tests/testapp/test_dynamicfield.py

@@ -336,7 +336,9 @@ class Invalid(models.Model):
         assert len(errors) == 1
         assert errors[0].id == "django_mysql.E009"
         assert "'spec' must be a dict" in errors[0].msg
-        assert "The value passed is of type list" in errors[0].hint
+        hint = errors[0].hint
+        assert hint is not None
+        assert "The value passed is of type list" in hint
 
     def test_spec_key_not_valid(self):
         class Invalid(models.Model):
@@ -346,8 +348,10 @@ class Invalid(models.Model):
         assert len(errors) == 1
         assert errors[0].id == "django_mysql.E010"
         assert "The key '2.0' in 'spec' is not a string" in errors[0].msg
-        assert "'spec' keys must be of type " in errors[0].hint
-        assert "'2.0' is of type float" in errors[0].hint
+        hint = errors[0].hint
+        assert hint is not None
+        assert "'spec' keys must be of type " in hint
+        assert "'2.0' is of type float" in hint
 
     def test_spec_value_not_valid(self):
         class Invalid(models.Model):
@@ -357,9 +361,10 @@ class Invalid(models.Model):
         assert len(errors) == 1
         assert errors[0].id == "django_mysql.E011"
         assert "The value for 'bad' in 'spec' is not an allowed type" in errors[0].msg
+        hint = errors[0].hint
+        assert hint is not None
         assert (
-            "'spec' values must be one of the following types: date, datetime"
-            in errors[0].hint
+            "'spec' values must be one of the following types: date, datetime" in hint
         )
 
     def test_spec_nested_value_not_valid(self):
@@ -374,9 +379,10 @@ class Invalid(models.Model):
         assert (
             "The value for 'bad' in 'spec.l1' is not an allowed type" in errors[0].msg
         )
+        hint = errors[0].hint
+        assert hint is not None
         assert (
-            "'spec' values must be one of the following types: date, datetime"
-            in errors[0].hint
+            "'spec' values must be one of the following types: date, datetime" in hint
         )