solar_position_method arg passed to basic_chain method wasn't used (#370)

* fix for issue #343

Now, passed 'offset' parameter are used instead of it's default value.

* test for issue #343

* solar_position_method passed to basic_chain wasn't used causing
execution of solarposition.get_solarposition with default 'nrel_numpy'
value in all cases.

* Update modelchain.py

doc string fixes for modelchain.basic_chain function

* Update v0.5.1.rst

* Update v0.5.1.rst

Author: KonstantinTr

docs/sphinx/source/whatsnew/v0.5.1.rst

@@ -10,6 +10,8 @@ API Changes
 Bug fixes
 ~~~~~~~~~
 * Remove condition causing Overflow warning from clearsky.haurwitz
+* modelchain.basic_chain now correctly passes 'solar_position_method' arg to solarposition.get_solarposition 
+* Doc string of modelchain.basic_chain was updated to describe args more accurately 
 
 Enhancements
 ~~~~~~~~~~~~
@@ -26,3 +28,4 @@ Testing
 Contributors
 ~~~~~~~~~~~~
 * Cliff Hansen
+* KonstantinTr

pvlib/modelchain.py

@@ -80,10 +80,10 @@ def basic_chain(times, latitude, longitude,
         Passed to system.get_irradiance.
 
     solar_position_method : str, default 'nrel_numpy'
-        Passed to location.get_solarposition.
+        Passed to solarposition.get_solarposition.
 
     airmass_model : str, default 'kastenyoung1989'
-        Passed to location.get_airmass.
+        Passed to atmosphere.relativeairmass.
 
     altitude : None or float, default None
         If None, computed from pressure. Assumed to be 0 m
@@ -129,6 +129,7 @@ def basic_chain(times, latitude, longitude,
                                                      longitude,
                                                      altitude=altitude,
                                                      pressure=pressure,
+                                                     method=solar_position_method,
                                                      **kwargs)
 
     # possible error with using apparent zenith with some models