class_docstr: Basic tests for the wrapped DeBruijnGraph class.
docstr: Test that pruning removes edges not between source and sink.
docstr_tok: ["Test","that","pruning","removes","edges","not","between","source","and","sink","."]
code: def test_pruning_2(self):
      """Test that pruning removes edges not between source and sink."""
      ref_str = "GATTACA"
      read_str = "CCGATGACACC"
      read = test_utils.make_read(
          read_str,
          chrom="chr20",
          start=1,
          cigar=[(len(read_str), "M")],
          quals=[30] * len(read_str),
          name="read",
      )
      # Use two reads so read path doesn't get pruned.
      dbg = debruijn_graph.build(
          ref_str, [read, read], self.single_k_dbg_options(3)
      )
  
      self.assertGraphEqual(
          """\
          digraph G {
          0[label=GAT];
          1[label=ATT];
          2[label=TTA];
          3[label=TAC];
          4[label=ACA];
          5[label=ATG];
          6[label=TGA];
          7[label=GAC];
          0->1 [label=1 color=red];
          1->2 [label=1 color=red];
          2->3 [label=1 color=red];
          3->4 [label=1 color=red];
          0->5 [label=2];
          5->6 [label=2];
          6->7 [label=2];
          7->4 [label=2];
          }
          """,
          dbg,
      )
  
imports: from absl.testing import absltest
  from absl.testing import parameterized
  from third_party.nucleus.io import fasta
  from third_party.nucleus.io import sam
  from third_party.nucleus.testing import test_utils
  from third_party.nucleus.util import ranges
  from deepvariant import testdata
  from deepvariant.protos import realigner_pb2
  from deepvariant.realigner.python import debruijn_graph
label_desc: Use image node_id 6 for calling the DeBruijnGraphWrapTest obj's underlying member method code with example usage: obj.test_pruning_2() without return types