added test for handling an invalid data file
added test for handling an invalid data file

souravsingh/khmer,ged-lab/khmer,F1000Research/khmer,ged-lab/khmer,souravsingh/khmer,Winterflower/khmer,souravsingh/khmer,kdmurray91/khmer,jas14/khmer,ged-lab/khmer,kdmurray91/khmer,jas14/khmer,F1000Research/khmer,jas14/khmer,Winterflower/khmer,F1000Research/khmer,kdmurray91/khmer,Winterflower/khmer