Registration form: better error for mixed case username

Fixes: #1327
Signed-off-by: Aurélien Bompard <aurelien@bompard.org>

.pre-commit-config.yaml

@@ -22,7 +22,7 @@ repos:
     rev: 5.12.0
     hooks:
       - id: isort
-        args: ["-c"]
+        args: ["-c", "--diff"]
 
   - repo: https://github.com/Lucas-C/pre-commit-hooks-bandit
     rev: v1.0.6

news/1327.feature

@@ -0,0 +1 @@
+Give a clearer error message to registering users who use a mixed case username

noggin/form/register_user.py

@@ -14,10 +14,11 @@
     Email,
     PasswordLength,
     StopOnError,
+    no_mixed_case,
     validator_proxy,
 )
 
-from .base import BaseForm, lower, ModestForm, strip, SubmitButtonField
+from .base import BaseForm, ModestForm, SubmitButtonField, lower, strip
 
 
 class RegisterUserForm(ModestForm):
@@ -45,6 +46,7 @@ class RegisterUserForm(ModestForm):
                     )
                 )
             ),
+            StopOnError(no_mixed_case),
             validator_proxy(
                 lambda: Regexp(
                     current_app.config["ALLOWED_USERNAME_PATTERN"],

pyproject.toml

@@ -185,7 +185,6 @@ twisted = "23.8.0"
 profile = "black"
 known_first_party = ["noggin", "noggin_messages"]
 lines_after_imports = 2
-force_alphabetical_sort_within_sections = true
 
 [tool.pytest.ini_options]
 testpaths = [

tests/unit/controller/test_registration.py

@@ -179,6 +179,23 @@ def test_step_1_bad_length(client, post_data_step_1, mocker, username):
     assert len(outbox) == 0
 
 
+def test_step1_mixed_case(client, post_data_step_1, mocker):
+    """Test giving username uppercase letters"""
+    post_data_step_1["register-username"] = "DummyUser"
+    record_signal = mocker.Mock()
+    with mailer.record_messages() as outbox, stageuser_created.connected_to(
+        record_signal
+    ):
+        result = client.post('/', data=post_data_step_1)
+    assert_form_field_error(
+        result,
+        "register-username",
+        "Mixed case is not allowed, try lower case.",
+    )
+    record_signal.assert_not_called()
+    assert len(outbox) == 0
+
+
 @pytest.mark.parametrize(
     "username", ["dummy_user", "dummy.user", "dummy user", "_dummy", ".dummy", "dummy-"]
 )