Add few tests to the module 'PopulationAdaptor'
Add few tests to the module 'PopulationAdaptor'

Ensembl/ensembl-variation,Ensembl/ensembl-variation,willmclaren/ensembl-variation,dbolser/ensembl-variation,willmclaren/ensembl-variation,dbolser/ensembl-variation,willmclaren/ensembl-variation,willmclaren/ensembl-variation,Ensembl/ensembl-variation,willmclaren/ensembl-variation,Ensembl/ensembl-variation,dbolser/ensembl-variation,Ensembl/ensembl-variation,dbolser/ensembl-variation