test(#552): add smoke test verifying R2 aria-required on username/password fields

R2 WCAG 3.3.1 requires that required form fields have aria-required='true'.
This smoke test verifies that the Gitea sign-in template includes
aria-required="true" on both username and password inputs.

Closes #552

tests/test_a11y_r2_aria_required.py

@@ -0,0 +1,84 @@
+#!/usr/bin/env python3
+"""Smoke test for a11y R2: aria-required on required form fields (#552).
+
+Verifies that required form inputs in the Gitea sign-in template
+include aria-required="true" for WCAG 3.3.1 compliance.
+"""
+
+from pathlib import Path
+
+REPO_ROOT = Path(__file__).parent.parent
+TEMPLATE_PATH = (
+    REPO_ROOT / "deploy" / "gitea-a11y" / "custom" / "templates" / "user" / "auth" / "signin_inner.tmpl"
+)
+
+
+def test_signin_username_has_aria_required():
+    """R2 requirement: username input must have aria-required='true'."""
+    assert TEMPLATE_PATH.exists(), f"Template not found: {TEMPLATE_PATH}"
+    
+    content = TEMPLATE_PATH.read_text()
+    
+    # Check that the template contains the username input section
+    assert 'id="user_name"' in content, "username input (id=user_name) not found"
+    assert 'name="user_name"' in content, "username input (name=user_name) not found"
+    
+    # Check for aria-required on username field
+    # The attribute should be in the input tag for user_name
+    assert 'aria-required="true"' in content, "aria-required='true' not found in template"
+    
+    print("  PASS: username field has aria-required='true'")
+
+
+def test_signin_password_has_aria_required():
+    """R2 requirement: password input must have aria-required='true'."""
+    assert TEMPLATE_PATH.exists(), f"Template not found: {TEMPLATE_PATH}"
+    
+    content = TEMPLATE_PATH.read_text()
+    
+    # Check that the template contains the password input section
+    assert 'id="password"' in content, "password input (id=password) not found"
+    assert 'type="password"' in content, "password input (type=password) not found"
+    
+    # Check for aria-required on password field
+    assert 'aria-required="true"' in content, "aria-required='true' not found in template"
+    
+    print("  PASS: password field has aria-required='true'")
+
+
+def test_both_required_fields_marked():
+    """R2: all required form fields must be marked with aria-required."""
+    assert TEMPLATE_PATH.exists(), f"Template not found: {TEMPLATE_PATH}"
+    
+    content = TEMPLATE_PATH.read_text()
+    
+    # Count required inputs — R2 applies to ALL required fields
+    required_inputs = []
+    in_input = False
+    current_input = []
+    for line in content.split('\n'):
+        if '<input' in line:
+            in_input = True
+            current_input = [line]
+        elif in_input:
+            current_input.append(line)
+            if '/>' in line or '>' in line:
+                in_input = False
+                input_str = '\n'.join(current_input)
+                if 'required' in input_str:
+                    required_inputs.append(input_str)
+                current_input = []
+    
+    assert len(required_inputs) >= 2, f"Expected at least 2 required inputs, found {len(required_inputs)}"
+    
+    for inp in required_inputs:
+        assert 'aria-required="true"' in inp, f"required input missing aria-required: {inp.strip()}"
+    
+    print(f"  PASS: all {len(required_inputs)} required input(s) have aria-required='true'")
+
+
+if __name__ == "__main__":
+    test_signin_username_has_aria_required()
+    test_signin_password_has_aria_required()
+    test_both_required_fields_marked()
+    print("\nAll R2 smoke tests passed.")