### Question:
X509Inspector { public String getAuthKeyId() { Extensions exts = x509holder.getExtensions(); AuthorityKeyIdentifier authKeyId = AuthorityKeyIdentifier.fromExtensions(exts); if (authKeyId == null) { return null; } byte[] octets = authKeyId.getKeyIdentifier(); String out = StaticHelpers.bytes2hex(octets); return out; } X509Inspector(X509CertificateHolder x509holder);  X509Inspector(X509Certificate x509); @Deprecated  X509Inspector(X509CertificateObject x509obj); X509CertificateHolder getX509CertificateHolder(); static X509Inspector newX509Inspector(X509CertificateHolder xh); static X509Inspector newX509Inspector(String x509PemString); static X509Inspector newX509Inspector(X509Certificate x509Cert); String getIssuerCN(); String getSubjectCN(); URI getOCSPUri(); URI getOCSPCaUri(); String getIssuerName(); String getSubjectName(); X509Certificate getX509Certificate(); BigInteger getPubModulus(); int getPubModulusSize(); BigInteger getSerial(); String getSubjKeyId(); String getAuthKeyId(); BigInteger getAuthKeyIdSerial(); List<String> getAuthKeyIdDirname(); PublicKey getPublicKey(); Calendar getNotBefore(); Calendar getNotAfter(); boolean isExpired(); boolean isPremature(); boolean isExpired(Date date); boolean isPremature(Date date); boolean isDateValid(); boolean isDateValid(Date date); @Deprecated X509CertificateObject getX509CertificateObject();  }### Answer:
@Test public void shouldGetNullIfKeyIdDoesNotExist() { Assert.assertNull(caCrtReader.getAuthKeyId()); }