Add a default error message.

When using multiple email field declarations it can be convienent to set
the error message once that you wish to use.

README.md

@@ -52,6 +52,12 @@ optionally you can configure the BDE API timeout in seconds (default 5)
 BDEA_TIMEOUT = 2
 ```
 
+A default error message can be set globally for the validation checking:
+
+```python
+BDEA_MESSAGE = '<blocked email message>'
+```
+
 Adding to your models
 ---------------------
 
@@ -86,4 +92,4 @@ try:
     validate_disposable_email(email)
 except ValidationError:
     pass
-```
+```

disposable_email_checker/validators.py

@@ -23,6 +23,8 @@ class DisposableEmailChecker():
     def __init__(self, message=None, code=None, whitelist=None):
         if message is not None:
             self.message = message
+        elif hasattr(settings, 'BDEA_MESSAGE'):
+            self.message = getattr(settings, 'BDEA_MESSAGE')
         if code is not None:
             self.code = code
         if whitelist is not None:

tests/test_validators.py

@@ -3,6 +3,7 @@
 import random
 from django.test import TestCase
 from django.core.exceptions import ValidationError
+from django.utils import six
 from disposable_email_checker import validators
 from disposable_email_checker.emails import email_domain_loader
 
@@ -18,3 +19,17 @@ def setUp(self):
     def test_validator(self):
         self.assertRaises(ValidationError, validators.validate_disposable_email, self.disposable_email)
         validators.validate_disposable_email(self.not_a_disposable_email)
+
+    def test_validator_messages(self):
+        with self.assertRaisesMessage(ValidationError, 'Blocked email provider.'):
+            validators.validate_disposable_email(self.disposable_email)
+
+        with self.settings(BDEA_MESSAGE='Test message'):
+            # As the `BDEA_MESSAGE` gets calculated at run time we need to reload the module that
+            #  defines the message.
+            six.moves.reload_module(validators)
+            with self.assertRaisesMessage(ValidationError, 'Test message'):
+                validators.validate_disposable_email(self.disposable_email)
+
+        # We need to reload the module again to set the default functionality back to normal.
+        six.moves.reload_module(validators)