test: add UserRole enum tests

backend/tests/test_user_role.py

@@ -0,0 +1,35 @@
+"""
+Tests for UserRole enum — verifies lowercase member names and values.
+"""
+import pytest
+from app.models.user import UserRole
+
+
+class TestUserRole:
+    def test_member_names_are_lowercase(self):
+        assert UserRole.pending.name == "pending"
+        assert UserRole.approved.name == "approved"
+        assert UserRole.admin.name == "admin"
+
+    def test_values_are_lowercase(self):
+        assert UserRole.pending.value == "pending"
+        assert UserRole.approved.value == "approved"
+        assert UserRole.admin.value == "admin"
+
+    def test_is_str_enum(self):
+        assert isinstance(UserRole.admin, str)
+        assert UserRole.admin == "admin"
+
+    def test_no_uppercase_members(self):
+        for member in UserRole:
+            assert member.name == member.name.lower(), f"Member {member.name} is not lowercase"
+            assert member.value == member.value.lower(), f"Value {member.value} is not lowercase"
+
+    def test_lookup_by_value(self):
+        assert UserRole("pending") == UserRole.pending
+        assert UserRole("approved") == UserRole.approved
+        assert UserRole("admin") == UserRole.admin
+
+    def test_invalid_value_raises(self):
+        with pytest.raises(ValueError):
+            UserRole("ADMIN")