### Question:
Key implements Serializable { @Override public String toString() { return GoodDataToStringBuilder.defaultToString(this); } @JsonCreator  Key(@JsonProperty("data") String data, @JsonProperty("type") String type); String getData(); String getType(); @Override String toString();  }### Answer:
@Test public void testToStringFormat() { final Key key = new Key(DATA, TYPE); assertThat(key.toString(), matchesPattern(Key.class.getSimpleName() + "\\[.*\\]")); }