Hi, I'm getting the same error on all the code I try for  the Trailhead Challenge 'Create a unit test for a simple Apex Class'.

The error I get is: Method does not exist or incorrect signature: void CheckDates(Date, Date) from the type VerifyDate

I have tried the following:

@isTest
private class TestVerifyDate {
    
    static testMethod void TestVerifyDates() {
        VerifyDate.CheckDates(system.today(),system.today().addDays(10));
        
        VerifyDate.CheckDates(system.today(),system.today().addDays(78));
       
    }

}


Also:

@isTest
public class TestVerifyDate {
    @isTest static void testVerifyDate(){
        date date1=VerifyDate.CheckDates(system.today(),system.today().addDays(10));
        System.assertEquals(system.today().addDays(10),date1);
        
        date date2=VerifyDate.CheckDates(system.today(),system.today().addDays(78));
        System.assertEquals(system.today(),date2);
    }
}


Also:

@isTest
private class TestVerifyDate{
    @isTest static void testDt1GtrDt2(){
        Date d2 = system.today();
        Date d1 = d2.addDays(10);
        
        Date dt = VerifyDate.CheckDates(d1, d2);
        Date testDt = Date.newInstance(2017, 7, 31);
        System.assertEquals(dt, testDt);
    }
    
    @isTest static void testDt2Within30dayOfDt1(){
        Date d1 = system.today();
        Date d2 = d1.addDays(10);
        
        Date dt = VerifyDate.CheckDates(d1, d2);
        System.assertEquals(dt, d2);
    }
}


This is the code for the Class itself:

public class VerifyDate {
//method to handle potential checks against two dates
public static Date CheckDates(Date date1, Date date2) {
//if date2 is within the next 30 days of date1, use date2. Otherwise use the end of the month
if(DateWithin30Days(date1,date2)) {
return date2;
} else {
return SetEndOfMonthDate(date1);
}
}
//method to check if date2 is within the next 30 days of date1
private static Boolean DateWithin30Days(Date date1, Date date2) {
//check for date2 being in the past
if( date2 < date1) { return false; }
//check that date2 is within (>=) 30 days of date1
Date date30Days = date1.addDays(30); //create a date 30 days away from date1
if( date2 >= date30Days ) { return false; }
else { return true; }
}
//method to return the end of the month of a given date
private static Date SetEndOfMonthDate(Date date1) {
Integer totalDays = Date.daysInMonth(date1.year(), date1.month());
Date lastDay = Date.newInstance(date1.year(), date1.month(), totalDays);
return lastDay;
}
}

Can anyone point me to what I am doing wrong please?

Thanks!