### Question:
Filter { public String getField() { return field.toString(); } Filter(Field field, Value<V> value);  Filter(Field field, Value<V> value, Operator operator); String getField(); V getValue(); Operator getOperator();  }### Answer:
@Test public void testFilterField() throws Exception { Mockito.doReturn("field").when(field).toString(); Filter<String> filter = new Filter<String>(field, value); Assert.assertEquals("field", filter.getField()); }