Help Unit Test cover method

Question

i wan't to make a unit test to cover my method, but he doesn't work and i don't know if i'm on a good way. I have this error : List has no rows for assignment to SObject

And this is my method code :

    public static void PB17_EventAddTypeRDV (List <Event> e, String operation) {

    for (Event evt : e){
        if( operation == 'Before')
        {    
            if (evt.Type != null && evt.Type != evt.Type_RDV__c) {
                evt.Type_RDV__c = evt.Type;
            }
        }
    }
}

And my test method :

    @istest
static void testEventAddTypeRDV(){
    Event evt = [SELECT Id, Type FROM Event LIMIT 1];
    List <Event> addEvt = new List<Event>();
    evt.Type = 'Rdv Physique';
    evt.Type_RDV__c = 'Rdv';
    addEvt.add(evt); 
    update addEvt;
}

Answer 1

In the test class your org data will be not be visible. So the query below is not giving you the data.

Event evt = [SELECT Id, Type FROM Event LIMIT 1];

It is always best practice to create the test data(event) in test class as below.

        Account acc= new Account ();
        a.name='Test Account';
        insert a;
        
        Event e = new Event();
        e.WhatId=a.id;
        e.StartDateTime=system.today();
        e.EndDateTime=system.today()+5;
        e.Type = 'Rdv Physique';
        insert e;
        

We can also use SeeAllData=true. But it is not advisable to use it . Please find the article for the same