//Takes the desired month (as an integer), gives the first of that month in the current FY
public static date giveMonthInFY(integer monthInt) {
    date dateToReturn;
    if (System.today().Month() >= 7) {
        dateToReturn = date.newinstance(Date.Today().Year(), monthInt, 1);
    }
    else {
        dateToReturn = date.newinstance(Date.Today().Year(), monthInt, 1)-365;
    }
    return dateToReturn;
}

@isTest
public static void testgiveMonthInFY(){
    date testDate3 = Date.newinstance(2018, 01,01);
    date sept1 = StarWarsTestDataUtil.giveMonthInFY(9);
    system.assertEquals(Date.newinstance(2017, 09, 01), sept1);
    date testDate4 = Date.newinstance(2018, 07,01);
    date sept1FY19 = StarWarsTestDataUtil.giveMonthInFY(9);
    system.assertEquals(Date.newinstance(2018, 09, 01), sept1FY19);
}