### Question:
Subscription { public Subscription withExpression(String expression) { setExpression(expression); return this; } Subscription(); DataExpr dataExpr(); String getId(); void setId(String id); Subscription withId(String id); String getExpression(); void setExpression(String expression); Subscription withExpression(String expression); long getFrequency(); void setFrequency(long frequency); Subscription withFrequency(long frequency); @Override boolean equals(Object o); @Override int hashCode(); @Override String toString();  }### Answer:
@Test public void dataExprInvalid() { Assertions.assertThrows(IllegalArgumentException.class, () -> new Subscription().withExpression(":true")); }