### Question:
PrivateKeyTypeAdapter extends XmlAdapter<String, PrivateKeyType> { @Override public PrivateKeyType unmarshal(final String v) { return MAPPING.get(v); }  @Override PrivateKeyType unmarshal(final String v); @Override String marshal(final PrivateKeyType v);  }### Answer:
@Test public void unmarshalLocked() { assertThat(adapter.unmarshal("argon2sbox")).isEqualTo(PrivateKeyType.LOCKED); }
@Test public void unmarshalUnlocked() { assertThat(adapter.unmarshal("unlocked")).isEqualTo(PrivateKeyType.UNLOCKED); }
@Test public void unmarshalNull() { assertThat(adapter.unmarshal(null)).isNull(); }