### Question:
FHIRExtractors { public static Pair<String, String> parseTag(String tag) { final int idx = tag.indexOf('|'); if (idx < 0) { return Pair.of("", tag); } return Pair.of(tag.substring(0, idx), tag.substring(idx + 1)); } private  FHIRExtractors(); static String getProviderNPI(Practitioner provider); static String getPatientMBI(Patient patient); static String getPatientBeneId(Patient patient); static UUID getEntityUUID(String idString); static Provenance.ProvenanceAgentComponent getProvenancePerformer(Provenance provenance); static Identifier parseIDFromQueryParam(String queryParam); static Pair<String, String> parseTag(String tag); static Identifier findMatchingIdentifier(List<Identifier> identifiers, DPCIdentifierSystem system); static String getOrganizationID(IBaseResource resource); static String getAttributedNPI(Group group);  }### Answer:
@Test void testTagParsing() { final Pair<String, String> codeTag = parseTag("a tag"); assertAll(() -> assertEquals("", codeTag.getLeft()), () -> assertEquals("a tag", codeTag.getRight())); final Pair<String, String> systemCodeTag = parseTag("This|is a tag"); assertAll(() -> assertEquals("This", systemCodeTag.getLeft()), () -> assertEquals("is a tag", systemCodeTag.getRight())); final Pair<String, String> danglingTag = parseTag("Dangling tag|"); assertAll(() -> assertEquals("Dangling tag", danglingTag.getLeft()), () -> assertEquals("", danglingTag.getRight())); final Pair<String, String> noSystem = parseTag("|Dangling tag"); assertAll(() -> assertEquals("", noSystem.getLeft()), () -> assertEquals("Dangling tag", noSystem.getRight())); }