old_contents: import pytest
  import parse_vcf as pv
  
  
  
  def test_openfile():
      assert pv.openfile('test_parse_vcf.py')[0] == True
  
new_contents: import pytest
  import parse_vcf as pv
  
  
  
  def test_openfile():
      # The real input file is called: 001.vcfmod 
      assert pv.openfile('001.vcfmod')[0] == True
  
subject: Use one of the real data files in test