test(#552): add smoke test verifying R2 aria-required on username field

Adds a regression test that checks the sign-in page override template
(deploy/gitea-a11y/custom/templates/user/auth/signin_inner.tmpl)
contains aria-required="true" on the username input field, per
accessibility audit R2 (#492). Also verifies required attribute presence
and correct label association.

Closes #552

tests/test_a11y_r2_aria_required.py

@@ -0,0 +1,79 @@
+#!/usr/bin/env python3
+"""
+Smoke test: a11y R2 aria-required attribute exists on required form fields.
+Issue #552: [a11y] R2: Add aria-required to required form fields
+
+Verifies that deploy/gitea-a11y/custom/templates/user/auth/signin_inner.tmpl
+includes aria-required="true" on required inputs:
+- Username input
+- Password input (also checked by R1, but verified here for completeness)
+"""
+
+import sys
+from pathlib import Path
+
+REPO_ROOT = Path(__file__).resolve().parent.parent
+TEMPLATE_PATH = REPO_ROOT / "deploy" / "gitea-a11y" / "custom" / "templates" / "user" / "auth" / "signin_inner.tmpl"
+
+
+def test_r2_username_input():
+    """Username input has required and aria-required."""
+    content = TEMPLATE_PATH.read_text()
+
+    # Input must have id and name user_name
+    assert 'id="user_name"' in content, "Username input missing id='user_name'"
+    assert 'name="user_name"' in content, "Username input missing name='user_name'"
+
+    # Must be a text input
+    assert 'type="text"' in content, "Username input missing type='text'"
+
+    # Required attribute present in the input element
+    # Check that required appears near the username input (simple presence in file)
+    # More precise: look for the pattern within the user_name input block
+    user_name_block = content[content.find('id="user_name"'):]
+    # limited scan for performance; find attributes inside the same <input ... />
+    assert 'required' in user_name_block[:200], "Username input missing required attribute"
+    assert 'aria-required="true"' in user_name_block[:200], "Username input missing aria-required='true'"
+
+    print("✓ Username input has required and aria-required")
+
+
+def test_r2_password_input():
+    """Password input also has aria-required (enforced by R1 but part of R2 scope)."""
+    content = TEMPLATE_PATH.read_text()
+
+    password_block = content[content.find('id="password"'):]
+    assert 'required' in password_block[:200], "Password input missing required"
+    assert 'aria-required="true"' in password_block[:200], "Password input missing aria-required='true'"
+
+    print("✓ Password input has required and aria-required")
+
+
+def test_r2_label_for_username():
+    """Label 'for' attribute matches username input id."""
+    content = TEMPLATE_PATH.read_text()
+
+    assert 'for="user_name"' in content, "Label missing for='user_name'"
+    print("✓ Label correctly associated with username input")
+
+
+def run_all():
+    print("R2 Smoke Test — aria-required on required fields (issue #552)")
+    print("-" * 60)
+    try:
+        test_r2_username_input()
+        test_r2_password_input()
+        test_r2_label_for_username()
+        print("-" * 60)
+        print("✅ All R2 checks passed")
+        return 0
+    except AssertionError as e:
+        print(f"\n❌ R2 check failed: {e}")
+        return 1
+    except Exception as e:
+        print(f"\n❌ Unexpected error: {e}")
+        return 1
+
+
+if __name__ == "__main__":
+    sys.exit(run_all())