### Question:
EntityIdentifier { @Override public String toString() { return type.getValue() + ":" + String.valueOf(id); } EntityIdentifier(EntityType type, UUID id); UUID getId(); EntityType getType(); @Override String toString(); static EntityIdentifier fromString(String entityString); @Override boolean equals(Object o); @Override int hashCode();  }### Answer:
@Test public void constructorWithNullEntityThrowsIllegalArgumentException() throws Exception { thrown.expect(IllegalArgumentException.class); new EntityIdentifier(null, UUID.randomUUID()).toString(); }
@Test public void constructorWithNullIdThrowsIllegalArgumentException() throws Exception { thrown.expect(IllegalArgumentException.class); new EntityIdentifier(EntityIdentifier.EntityType.SERVICE, null).toString(); }