# forge.testing.assert_no_lookahead

```python
forge.testing.assert_no_lookahead(strategy: str | os.PathLike[str] | type[Strategy], bars: SampleBars | pd.DataFrame | None = None, params: Mapping[str, Any] | None = None, **kwargs: Any) -> None
```

Fail unless the look-ahead audit shows no evidence of look-ahead.

The failure names the verdict, the reason when there is one, and the first three differences
with
their series and bars. A verdict of ``inconclusive`` fails too: an audit that could not judge
has
shown nothing. The arguments are those of ``check_lookahead``.

Since Forge API 1.