### Question:
Undefined extends EqualTo { private Undefined() { super(UndefinedValue.getInstance()); } private  Undefined(); static Undefined getInstance(); @Override String toString();  }### Answer:
@Test public void shouldComplainWhenProvidedWithIllegalValues() { try { undefined().evaluate(new Byte[]{}); fail(); } catch (IllegalArgumentException e) { } try { undefined().evaluate(null); fail(); } catch (IllegalArgumentException e) { } try { undefined().evaluate(new HashMap<>()); fail(); } catch (IllegalArgumentException e) { } }