DateTime.from_iso8601 returns unexpected tuple

[brianmay]

teslamate/lib/teslamate/log.ex

Lines 176 to 185 in ad34131

	date_earliest =
	cond do
	min_id == 0 ->
	DateTime.add(DateTime.utc_now(), -10, :day)
	true ->
	DateTime.from_iso8601("2003-07-01T00:00:00Z")
	end
	naive_date_earliest = DateTime.to_naive(date_earliest)

If you look at the logs, there was is scary looking error that isn't generating a test failure:

** (FunctionClauseError) no function clause matching in DateTime.to_naive/1
    (elixir 1.16.2) lib/calendar/datetime.ex:925: DateTime.to_naive({:ok, ~U[2003-07-01 00:00:00Z], 0})
    (teslamate 1.30.2-dev) lib/teslamate/log.ex:185: TeslaMate.Log.get_positions_without_elevation/2
    (teslamate 1.30.2-dev) lib/teslamate/terrain.ex:77: TeslaMate.Terrain.handle_event/4
    (stdlib 5.2.3.2) gen_statem.erl:1397: :gen_statem.loop_state_callback/11
    (stdlib 5.2.3.2) proc_lib.erl:241: :proc_lib.init_p_do_apply/3

Problem is DateTime.from_iso8601 returns a tuple, and could in theory fail. Sigh. Wish Elixir had strong type checking...

In actual practice, this function call probably I think can't fail, the value is constant.

[brianmay]

I suspect (but haven't checked) the reason this didn't cause the tests to fail is because the errors occurred in another process, not the test process.

Which is somewhat unfortunate.