Explicitly state datetime units in array constructors in `test_datetime_mean` (#5463)
Explicitly state datetime units in array constructors in `test_datetime_mean` (#5463)


markelg/xray,markelg/xray,pydata/xarray,pydata/xarray,jhamman/xarray,pydata/xarray,jhamman/xarray,markelg/xray,jhamman/xarray