Question

I have this method to test :

public static Date getDateSinceUTC(CstOrderBean orderBean) {

    int year = orderBean.getDeadLineYear();
    int month = orderBean.getDeadLineMonth();
    int day = orderBean.getDeadLineDay();
    int hour = orderBean.getDeadLineHour();
    int minute = orderBean.getDeadLineMinute();
    String ap = orderBean.getDeadLineAmPm() == 1 ? "PM" : "AM";

    //TODO   AM=0, PM=1  comes from html form
    SimpleDateFormat df = new SimpleDateFormat("yyyy:MM:dd:hh:mm:aa");
    String stringDate = stringifyIntegers(":", year, month, day, hour, minute); 
    stringDate = stringDate.concat(ap);

    Date date;
    try {
        date = df.parse(stringDate);
    } catch (ParseException e) {
        throw new Error("Parsing date from html form failed", e);
    }
    return date;
}

Where CstOrderBean needs to be mocked by Mockito because it is not a POJO (some static initializations etc. – from source code generator). But I need to run the method xxx times, hence set the mocks with many data combinations

I could use TestNG’s @DataProvider to do that. But I’m not sure how to do that, I guess that :

    when(ob.getDeadLineYear()).thenReturn(1, 2, 3);
     ....

in loop is a bad idea, isn’t it ? Is the correct way of doing this to create xx mocks and initialize them like that ?

Answer 1

Each test should get their own mock that preferably does not have variable data. If you use several different return values from the same mock object then the testing has to be white-box testing as the test is coupled with the number of calls to a mocked method instead of the result of the method under test.

That said, you are able to define a set of return values with calling thenReturn repeatedly or by defining the return values as varargs

when(ob.getDeadLineYear()).thenReturn(someValue, anotherValue, ..., ultimateValue);

This might be cleaner as you should probably control the values that the mock returns anyway.