class_docstr: Test the ability to round-trip VCF files.
code: def setUp(self):
      self.header = (
          '##fileformat=VCFv4.2\n##FILTER=<ID=PASS,Description="All filters '
          'passed">\n##INFO=<ID=DB,Number=0,Type=Flag,Description="In '
          'dbSNP">\n##INFO=<ID=MIN_DP,Number=1,Type=Integer,Description="Min '
          'DP">\n##FORMAT=<ID=GT,Number=1,Type=String,Description="Genotype">\n##FORMAT=<ID=AD,Number=R,Type=Integer,Description="Allelic'
          ' depths">\n##FORMAT=<ID=DP,Number=1,Type=Integer,Description="Read '
          'depth">\n##FORMAT=<ID=PL,Number=G,Type=Integer,Description="Genotype '
          'likelihood,Phred-encoded">\n##contig=<ID=chr1,length=248956422>\n#CHROM\tPOS\tID\tREF\tALT\tQUAL\tFILTER\tINFO\tFORMAT\tS1\tS2\n'
      )
      self.record_format_strings = [
          "chr1\t13613\t.\tT\tA\t39.88\tPASS\t{info}\t{fmt}\t0/1{efmts1}\t1/1{efmts2}\n",
          "chr1\t13813\trs1\tT\tG\t90.28\tPASS\t{info}\t{fmt}\t1/1{efmts1}\t0|1{efmts2}\n",
          "chr1\t13838\t.\tC\tT\t62.74\tPASS\t{info}\t{fmt}\t0/1{efmts1}\t0/1{efmts2}\n",
      ]
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from absl.testing import absltest
  from absl.testing import parameterized
  from etils import epath
  from third_party.nucleus.io import vcf
  from third_party.nucleus.protos import reference_pb2
  from third_party.nucleus.protos import struct_pb2
  from third_party.nucleus.protos import variants_pb2
  from third_party.nucleus.testing import test_utils
  from third_party.nucleus.util import ranges
label_desc: Use image node_id 1 for calling the VcfRoundtripTests obj's underlying member method code with example usage: obj.setUp() without return types