test(collection_order): add red tests for opt-in sort_items_by_order

tests/test_pytest_collection_order.py

@@ -0,0 +1,37 @@
+from pathlib import Path
+import pytest
+
+def test_no_op_without_registry(tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
+ monkeypatch.chdir(tmp_path)
+ (tmp_path / "test_zz.py").write_text(
+  "def test_b(): pass\ndef test_a(): pass\n", encoding="utf-8"
+ )
+ from pytest_collection_order import sort_items_by_order
+ items = []
+ result = sort_items_by_order(items, registry_path=tmp_path / "reg.toml")
+ assert result == items
+
+def test_sorts_by_order_index(tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
+ monkeypatch.chdir(tmp_path)
+ (tmp_path / "test_zz.py").write_text(
+  "def test_b(): pass\ndef test_a(): pass\n", encoding="utf-8"
+ )
+ reg = tmp_path / "reg.toml"
+ reg.write_text(
+  "[[files.test_zz.test_order]]\n"
+  "test_id = 'test_zz::test_b'\n"
+  "order = 1\n"
+  "[[files.test_zz.test_order]]\n"
+  "test_id = 'test_zz::test_a'\n"
+  "order = 2\n",
+  encoding="utf-8",
+ )
+ class _Item:
+  def __init__(self, nodeid: str) -> None:
+   self.nodeid = nodeid
+  def __repr__(self) -> str:
+   return f"_Item({self.nodeid!r})"
+ items = [_Item("test_zz::test_b"), _Item("test_zz::test_a")]
+ from pytest_collection_order import sort_items_by_order
+ result = sort_items_by_order(items, registry_path=reg)
+ assert [i.nodeid for i in result] == ["test_zz::test_b", "test_zz::test_a"]