Add guard test for tool mapping helper usage

Co-authored-by: Shri Sukhani <shrisukhani@users.noreply.github.com>

Author: cursoragent

tests/test_tool_mapping_reader_usage.py

@@ -0,0 +1,44 @@
+import ast
+from pathlib import Path
+
+
+TOOLS_MODULE = Path("hyperbrowser/tools/__init__.py")
+
+
+def _collect_keys_calls(module: ast.AST) -> list[int]:
+    keys_calls: list[int] = []
+    for node in ast.walk(module):
+        if not isinstance(node, ast.Call):
+            continue
+        if not isinstance(node.func, ast.Attribute):
+            continue
+        if node.func.attr == "keys":
+            keys_calls.append(node.lineno)
+    return keys_calls
+
+
+def _collect_helper_calls(module: ast.AST, helper_name: str) -> list[int]:
+    helper_calls: list[int] = []
+    for node in ast.walk(module):
+        if not isinstance(node, ast.Call):
+            continue
+        if not isinstance(node.func, ast.Name):
+            continue
+        if node.func.id == helper_name:
+            helper_calls.append(node.lineno)
+    return helper_calls
+
+
+def test_tools_module_uses_shared_mapping_read_helpers():
+    source = TOOLS_MODULE.read_text(encoding="utf-8")
+    module = ast.parse(source, filename=str(TOOLS_MODULE))
+
+    keys_calls = _collect_keys_calls(module)
+    read_key_calls = _collect_helper_calls(module, "read_string_mapping_keys")
+    copy_value_calls = _collect_helper_calls(
+        module, "copy_mapping_values_by_string_keys"
+    )
+
+    assert keys_calls == []
+    assert read_key_calls != []
+    assert copy_value_calls != []