Method test_argmax

xarray/tests/test_dataarray.py:5256–5290

(
        self,
        x: np.ndarray,
        minindex: int | float,
        maxindex: int | float,
        nanindex: int | None,
    )

        "ignore:Behaviour of argmin/argmax with neither dim nor :FutureWarning"
    )
    def test_argmax(
        self,
        x: np.ndarray,
        minindex: int | float,
        maxindex: int | float,
        nanindex: int | None,
    ) -> None:
        ar = xr.DataArray(
            x, dims=["x"], coords={"x": np.arange(x.size) * 4}, attrs=self.attrs
        )
        indarr = xr.DataArray(np.arange(x.size, dtype=np.intp), dims=["x"])

        if np.isnan(maxindex):
            with pytest.raises(ValueError):
                ar.argmax()
            return

        expected0 = indarr[maxindex]
        expected0.attrs = self.attrs  # Default keeps attrs for reduction operations
        result0 = ar.argmax()
        assert_identical(result0, expected0)

        result1 = ar.argmax(keep_attrs=True)
        expected1 = expected0.copy()
        expected1.attrs = self.attrs
        assert_identical(result1, expected1)

        result2 = ar.argmax(skipna=False)
        if nanindex is not None and ar.dtype.kind != "O":
            expected2 = indarr.isel(x=nanindex, drop=True)
            expected2.attrs = self.attrs  # Default keeps attrs for reduction operations
        else:
            expected2 = expected0

        assert_identical(result2, expected2)

    @pytest.mark.parametrize(
        "use_dask",