### Question:
Credentials { public static Credentials create(ECKeyPair ecKeyPair) { String address = Numeric.prependHexPrefix(Keys.getAddress(ecKeyPair)); return new Credentials(ecKeyPair, address); } private  Credentials(ECKeyPair ecKeyPair, String address); ECKeyPair getEcKeyPair(); String getAddress(); static Credentials create(ECKeyPair ecKeyPair); static Credentials create(String privateKey, String publicKey); static Credentials create(String privateKey); @Override boolean equals(Object o); @Override int hashCode();  }### Answer:
@Test public void testCredentialsFromECKeyPair() { Credentials credentials = Credentials.create( SampleKeys.PRIVATE_KEY_STRING, SampleKeys.PUBLIC_KEY_STRING); verify(credentials); }
@Test public void testCredentialsFromString() { Credentials credentials = Credentials.create(SampleKeys.KEY_PAIR); verify(credentials); }
@Test public void testCredentialsFromECKeyPair() { Credentials credentials = Credentials.create(SampleKeys.PRIVATE_KEY_STRING, SampleKeys.PUBLIC_KEY_STRING); verify(credentials); }