### Question:
DateTimeFunction extends SimpleJtwigFunction { @Override public Object execute(FunctionRequest request) { Long milli = (Long) request.getArguments().get(0); return DateTimeUtils.formatMilliToString(milli); }  @Override String name(); @Override Object execute(FunctionRequest request);  }### Answer:
@Test public void execute() { FunctionRequest request = mock(FunctionRequest.class); doReturn(Collections.singletonList(1588335692988L)).when(request).getArguments(); assertEquals("01 May 2020 12:21", function.execute(request)); }