### Question:
ClinVarVCFHeaderExtender extends VCFHeaderExtender { @Override public void addHeaders(VCFHeader header, String prefix) { addHeaders(header, prefix, "", ""); final String note = " (requiring no genotype match, only position overlap)"; if (options.isReportOverlapping() && !options.isReportOverlappingAsMatching()) addHeaders(header, prefix, "OVL_", note); } ClinVarVCFHeaderExtender(DBAnnotationOptions options); @Override String getDefaultPrefix(); @Override void addHeaders(VCFHeader header, String prefix);  }### Answer:
@Test public void test() { VCFHeader header = new VCFHeader(); Assert.assertEquals(0, header.getFilterLines().size()); Assert.assertEquals(0, header.getInfoHeaderLines().size()); Assert.assertEquals(0, header.getFormatHeaderLines().size()); Assert.assertEquals(0, header.getIDHeaderLines().size()); Assert.assertEquals(0, header.getOtherHeaderLines().size()); DBAnnotationOptions options = DBAnnotationOptions.createDefaults(); options.setReportOverlapping(true); options.setReportOverlappingAsMatching(false); options.setIdentifierPrefix("CLINVAR_"); new ClinVarVCFHeaderExtender(options).addHeaders(header); Assert.assertEquals(0, header.getFilterLines().size()); Assert.assertEquals(6, header.getInfoHeaderLines().size()); Assert.assertEquals(0, header.getFormatHeaderLines().size()); Assert.assertEquals(6, header.getIDHeaderLines().size()); Assert.assertEquals(0, header.getOtherHeaderLines().size()); Assert.assertNotNull(header.getInfoHeaderLine("CLINVAR_BASIC_INFO")); Assert.assertNotNull(header.getInfoHeaderLine("CLINVAR_VAR_INFO")); Assert.assertNotNull(header.getInfoHeaderLine("CLINVAR_DISEASE_INFO")); }