global class setExams2Expired implements Schedulable {
    global void execute(SchedulableContext ctx) {

        List<Certification__c> objects = [
        SELECT Id, Expiration_Date__c, Exam_state__c
        FROM Certification__c
        WHERE Exam_state__c in ('Active')];

        for(Certification__c c : objects){
            if(c.Expiration_Date__c < date.today()){
                c.Exam_state__c = 'Expired';
            }
            else if(c.Expiration_Date__c == date.today().addDays(+7)){
                c.Day7ExpiryAlert__c = True;
            }
        }
        update objects;
    }
}

@isTest
public class setExams2ExpiredTest {
    @isTest
    public static void ifNotExpired() {

        Account acc1 = new Account(name='Test Account 1',phone='121212', Global_POD__c ='AP');
        insert acc1;
        Account acc2 = new Account(name='Test Account 2',phone='343434', Global_POD__c ='AP');
        insert acc2;

        Contact con1 = new Contact(accountid=acc1.id,lastname='Test Contact 1',email='abcd@gmail.com');
        insert con1;
        Contact con2 = new Contact(accountid=acc2.id,lastname='Test Contact 2',email='efgh@gmail.com');
        insert con2;

        Certification__c c = new Certification__c(Contact__c=con1.id, Name = 'abcd', Expiration_Date__c = Date.today().addDays(+2), Exam_state__c = 'Active');
        insert c;

        Test.startTest();
        setExams2Expired ctx = new setExams2Expired();
        ctx.execute(null);
        System.assertEquals('Active','Active','ifNotExpired doesn't work - meaning an exam is either set to expired when it shouldn't have been or nothing happenend for a certain record');
        Test.stopTest();
    }
    @isTest
    public static void sendEmail(){

        Account acc5 = new Account(name='Test Account 5',phone='787878', Global_POD__c ='AP');
        insert acc5;
        Account acc6 = new Account(name='Test Account 6',phone='898989', Global_POD__c ='AP');
        insert acc6;

        Contact con5 = new Contact(accountid=acc5.id,lastname='Test Contact 5',email='qrstuv@gmail.com');
        insert con5;
        Contact con6 = new Contact(accountid=acc6.id,lastname='Test Contact 6',email='wxyz@gmail.com');
        insert con6;

        Certification__c c = new Certification__c(Contact__c=con5.id, Name = 'efgh', Expiration_Date__c = Date.today().addDays(+7), Exam_state__c = 'Active', Day7ExpiryAlert__c = false);
        insert c;

        Test.startTest();
        setExams2Expired ctx = new setExams2Expired();
        ctx.execute(null);
        System.assertEquals(false, false,'No alert was sent here');
        Test.stopTest();
    }
}