Validate page params constructor return type

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

Author: cursoragent

hyperbrowser/client/managers/page_params_utils.py

@@ -23,11 +23,16 @@ def build_page_batch_params(
     if batch_size <= 0:
         raise HyperbrowserError("batch_size must be a positive integer")
     try:
-        return cast(T, params_model(page=page, batch_size=batch_size))
+        params_obj = params_model(page=page, batch_size=batch_size)
     except HyperbrowserError:
         raise
     except Exception as exc:
         raise HyperbrowserError(
             "Failed to build paginated page params",
             original_error=exc,
         ) from exc
+    if type(params_obj) is not params_model:
+        raise HyperbrowserError(
+            "Paginated page params model constructor returned invalid type"
+        )
+    return cast(T, params_obj)

tests/test_page_params_helper_usage.py

@@ -22,3 +22,7 @@ def test_paginated_managers_use_shared_page_params_helper():
         module_text = Path(module_path).read_text(encoding="utf-8")
         assert "build_page_batch_params(" in module_text
         assert "batch_size=100" not in module_text
+        assert "GetBatchScrapeJobParams(page=page" not in module_text
+        assert "GetCrawlJobParams(page=page" not in module_text
+        assert "GetBatchFetchJobParams(page=page" not in module_text
+        assert "GetWebCrawlJobParams(page=page" not in module_text

tests/test_page_params_utils.py

@@ -74,3 +74,15 @@ def __init__(self, *, page, batch_size):  # noqa: ARG002
         build_page_batch_params(_BrokenParams, page=1)
 
     assert exc_info.value.original_error is None
+
+
+def test_build_page_batch_params_rejects_constructor_returning_wrong_type():
+    class _BrokenParams:
+        def __new__(cls, *, page, batch_size):  # noqa: ARG003
+            return {"page": page, "batch_size": batch_size}
+
+    with pytest.raises(
+        HyperbrowserError,
+        match="Paginated page params model constructor returned invalid type",
+    ):
+        build_page_batch_params(_BrokenParams, page=1)