Conflicts:
geopandas/geodataframe.py
tests/test_geodataframe.py
I resolved conflicts and ensured existing tests pass.
I did not check for consistency with any discussions that may have been
made in the interim, around how missing geoms ought to be treated.
explode() expands multi-part geometries into multiple rows, and into
their single part geometries.
collect() and take multiple single geometries and combine them into their
Multi* counterparts.
For geometry tests, test both the GeoSeries and GeoDataFrame versions.
If the method's input is also a GeoSeries, test the input for both
GeoSeries and GeoDataFrame as well.
For example, for intersects(), test the following combination of inputs:
GeoSeries, GeoSeries,
GeoDataFrame, GeoSeries,
GeoSeries, GeoDataFrame,
GeoDataFrame, GeoDataFrame
Helper functions are provided to test all combinations