Add tests for variation related methods.
Add tests for variation related methods.

danstaines/ensembl,danstaines/ensembl,danstaines/ensembl,Ensembl/ensembl,Ensembl/ensembl,Ensembl/ensembl,james-monkeyshines/ensembl,muffato/ensembl,Ensembl/ensembl,james-monkeyshines/ensembl,muffato/ensembl,james-monkeyshines/ensembl,muffato/ensembl,james-monkeyshines/ensembl,muffato/ensembl