Make sure times are assigned with ModelChain.run_from_poa (#1162)

* Make sure times are assigned with ModelChain.run_from_poa

* move _assign_times to _assign_weather

Author: alorenzo175

pvlib/modelchain.py

@@ -1324,6 +1324,7 @@ def _build_weather(data):
                 _build_weather(weather) for weather in data
             )
         self._configure_results()
+        self._assign_times()
         return self
 
     def _assign_total_irrad(self, data):
@@ -1392,7 +1393,6 @@ def prepare_inputs(self, weather):
         self._check_multiple_input(weather, strict=False)
         self._verify_df(weather, required=['ghi', 'dni', 'dhi'])
         self._assign_weather(weather)
-        self._assign_times()
 
         self._prep_inputs_solar_pos(weather)
         self._prep_inputs_airmass()

pvlib/tests/test_modelchain.py

@@ -774,6 +774,7 @@ def test_prepare_inputs_from_poa(sapm_dc_snl_ac_system, location,
     assert_frame_equal(mc.weather, weather_expected)
     # total_irrad attribute
     assert_frame_equal(mc.results.total_irrad, total_irrad)
+    assert not pd.isnull(mc.results.solar_position.index[0])
 
 
 @pytest.mark.parametrize("input_type", [tuple, list])