--- a
+++ b/deepvariant/dv_vcf_constants_test.py
@@ -0,0 +1,65 @@
+# Copyright 2017 Google LLC.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+#
+# 1. Redistributions of source code must retain the above copyright notice,
+#    this list of conditions and the following disclaimer.
+#
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in the
+#    documentation and/or other materials provided with the distribution.
+#
+# 3. Neither the name of the copyright holder nor the names of its
+#    contributors may be used to endorse or promote products derived from this
+#    software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+"""Tests for deepvariant .dv_vcf_constants."""
+
+from absl.testing import absltest
+from absl.testing import parameterized
+from third_party.nucleus.protos import reference_pb2
+from deepvariant import dv_vcf_constants
+
+
+class DvVcfConstantsTest(parameterized.TestCase):
+
+  @parameterized.parameters(
+      dict(contigs=[], sample_names=[]),
+      dict(
+          contigs=[reference_pb2.ContigInfo(name='chr1')],
+          sample_names=['single_sample'],
+      ),
+      dict(
+          contigs=[
+              reference_pb2.ContigInfo(name='1'),
+              reference_pb2.ContigInfo(name='2'),
+          ],
+          sample_names=['multiple', 'samples'],
+      ),
+  )
+  def test_deepvariant_header(self, contigs, sample_names):
+    header = dv_vcf_constants.deepvariant_header(
+        contigs=contigs, sample_names=sample_names
+    )
+    self.assertCountEqual(header.contigs, contigs)
+    self.assertCountEqual(header.sample_names, sample_names)
+    self.assertGreater(len(header.filters), 0)
+    self.assertGreater(len(header.infos), 0)
+    self.assertGreater(len(header.formats), 0)
+
+
+if __name__ == '__main__':
+  absltest.main()