NRL-1215 Fix case sensitive detection

Author: axelkrastek1-nhs

layer/nrlf/core/json_duplicate_checker.py

@@ -5,13 +5,16 @@
 def check_for_duplicate_keys(pairs: list[tuple[str, Any]]) -> dict:
     keys = {}
     dupes = {}
+    normalized_keys = []
 
     for key, value in pairs:
+        normalized_key = key.lower()
         print(f"Processing key: {key}, value: {value}")
-        if key in keys:
+        if normalized_key in normalized_keys:
             dupes.setdefault(key, []).append(value)
         else:
             keys[key] = value
+            normalized_keys += [normalized_key]
 
     if dupes:
         keys["__duplicates__"] = dupes

layer/nrlf/core/tests/test_json_duplicate_checker.py

@@ -324,3 +324,9 @@ def test_array_edge_case_duplicate(self):
         duplicates, paths = check_duplicate_keys(json_content)
         self.assertEqual(duplicates, ["array"])
         self.assertEqual(paths, ["root.array"])
+
+    def test_case_sensitive_keys(self):
+        json_content = '{"a": 1, "A": 2, "aA": 3, "Aa": 4}'
+        duplicates, paths = check_duplicate_keys(json_content)
+        self.assertEqual(duplicates, ["A", "Aa"])
+        self.assertEqual(paths, ["root.A", "root.Aa"])