### Question:
RangeExpression extends Expression { @Override public String toString() { return getPropertyName() + " " + getOperator() + " " + from + "," + to; } RangeExpression(Operator operator, String propertyName, Object from,
            Object to); Object getFrom(); Object getTo(); @Override String toString(); @Override int hashCode(); @Override boolean equals(Object obj);  }### Answer:
@Test public void testToString() { String expected = propertyName + " " + operator + " " + from + "," + to; assertEquals(expected, e.toString()); }