@Test(dataProvider = "MissingFormatTestData")
public void testMissingFormatFields(final VCFEncoder encoder, final VariantContext vc, final String expectedLastColumn, final Map<Allele, String> alleleMap, final List<String> genotypeFormatKeys) {
final StringBuilder sb = new StringBuilder();
final String[] columns = new String[5];
encoder.addGenotypeData(vc, alleleMap, genotypeFormatKeys, sb);
final int nCol = ParsingUtils.split(sb.toString(), columns, VCFConstants.FIELD_SEPARATOR_CHAR);
Assert.assertEquals(columns[nCol-1], expectedLastColumn, "Format fields don't handle missing data in the expected way");
}