108536374: Implement a validator to exclude passwords on a blacklist

tests/app/main/test_validators.py

@@ -0,0 +1,17 @@
+from pytest import fail
+
+from app.main.forms import RegisterUserForm
+
+
+def test_should_raise_validation_error_for_password(notifications_admin):
+    form = RegisterUserForm()
+    form.name.data = 'test'
+    form.email_address.data = 'teset@example.gov.uk'
+    form.mobile_number.data = '+441231231231'
+    form.password.data = 'password1234'
+
+    try:
+        form.validate()
+        fail()
+    except:
+        assert 'That password is blacklisted, too common' in form.errors['password']