### Question:
GroovyEngineFactory extends GroovyScriptEngineFactory { public void setSandbox(final GroovyValueFilter sandbox) { Reject.ifNull(sandbox); this.sandbox = sandbox; } GroovyEngineFactory(); @Override ScriptEngine getScriptEngine(); void setSandbox(final GroovyValueFilter sandbox);  }### Answer:
@Test(expectedExceptions = NullPointerException.class) public void shouldRejectNullSandbox() { testFactory.setSandbox(null); }