def METHOD_NAME(self):
    res = self.gdf.merge(self.df, left_on="values", right_on="col1")
    # check result is a GeoDataFrame
    assert isinstance(res, GeoDataFrame)
    # check geometry property gives GeoSeries
    assert isinstance(res.geometry, GeoSeries)
    # check metadata
    self._check_metadata(res)
    # test that crs and other geometry name are preserved
    self.gdf.crs = "epsg:4326"
    self.gdf = self.gdf.rename(columns={"geometry": "points"}).set_geometry(
        "points"
    )
    res = self.gdf.merge(self.df, left_on="values", right_on="col1")
    assert isinstance(res, GeoDataFrame)
    assert isinstance(res.geometry, GeoSeries)
    self._check_metadata(res, "points", self.gdf.crs)