test: add explicit test for weekday change

tests/optimize/test_optimize_reports.py

@@ -639,6 +639,7 @@ def test__get_resample_from_period():
     assert _get_resample_from_period("day") == "1d"
     assert _get_resample_from_period("week") == "1W-MON"
     assert _get_resample_from_period("month") == "1ME"
+    assert _get_resample_from_period("weekday") == "weekday"
     with pytest.raises(ValueError, match=r"Period noooo is not supported."):
         _get_resample_from_period("noooo")