What must be done when a list has no rows for assignment to

Question

I'm having an issue with my Apex Test Class from a trigger. I've used the trigger multiple times in my sandbox but when I try to test it out it fails. The reason for the failure is 'System.QueryException: List has no rows for assignment to SObject' which I have tried to look up but there are so many answers and they don't apply to my case. Tried it multiple ways and I am wondering if anybody here has a good answer.

I have two objects, Implementation (custom) and Opportunity. The trigger fires when an Opportunity is set to 'Closed Won'. Below is the trigger:

    trigger CreateImplementation on Opportunity (after update) {
    List opps = new List();
    for ( Opportunity opp : Trigger.new ){

        if((opp.StageName == 'Closed Won' ) &&
        (Trigger.oldMap.get(opp.Id).StageName!='Closed Won') ) {
        opps.add(opp.Id);
    }
    Map oppsMap = new Map( [SELECT Id, Account.Id, CloseDate, OwnerId, Account.Name from Opportunity where Id IN :opps] );
    List  impToInsert = new List  ();
    for( Opportunity oppo : oppsMap.values()){
        Implementation__c imp = new Implementation__c ();
        imp.Account__c = oppo.AccountId;
        imp.Name = oppo.Account.Name +' Implementation';
        imp.Phase__c = 'Phase 0';
        imp.Contract_Date__c = oppo.CloseDate;
        impToInsert.add(imp);
    }
try {
        insert impToInsert;
    } catch (system.Dmlexception e) {
        system.debug (e);
    }
    }
}
And here is the test class
@istest private class CreateImplementation {
    testMethod private static void CreateImplementation () {
        Account acco = new Account(Name = 'Acme Test Account', Type = 'Prospect');
        insert acco;
        Opportunity opp = new Opportunity(Name = 'Acme Test Opp', CloseDate=System.Today(), AccountId=acco.id, Type= 'New Business', Business_Value__c='NA',Closed_Reasons__c='NA', StageName='Closed Won',Amount=1000);
        insert opp;
        Implementation__c imp = [ SELECT Account__c, Name, Phase__c FROM Implementation__c WHERE Account__c = :acco.id LIMIT 1 ];
        System.assertEquals(imp.Phase__c,'Phase 0');
    }
}

Aashish Chaursiya · Accepted Answer

When a list has no rows for assignment to sobject - Your trigger is only firing after update and your test does not perform any updates, only the insert of an account and opportunity. Do you intend for Implementation records to be inserted on the insert of a new opportunity? If so, you should make your trigger after insert as well. Alternatively, you can insert the opp and then update it in your test.The likely reason for your List having no row error is that you are trying to SOQL into a single sObject and not a list and this will throw an error when no rows are returned. In this case, no rows are returned from your Implementation query because of the issue with after update and how you've structured your test. Instead, try querying into a list of sObject and this will prevent an exception from occurring in your test: List impls = [SELECT... // And assuming you arrange your test to produce 1 object... System.assertEquals(1, impls.size()); System.assertEquals('Phase 0', impls[0].Phase__c);

Ranjana Admin · Answer

The error message "list index out of range" typically occurs when you're trying to access an index in a list that doesn't exist. This can happen if you're trying to access an index beyond the range of the list. Here's what you can do to address it:

Check the Length of the List: Before accessing an index in the list, verify that the list contains elements and has a length greater than zero. You can use the len() function to check the length of the list.

my_list = [1, 2, 3]
if len(my_list) > 0:
    # Access list elements safely
    print(my_list[0])

Ensure Index is Within Range: If you're accessing a specific index in the list, make sure that the index is within the valid range of indices for the list. Remember that Python uses zero-based indexing, so the first element is at index 0, the second element is at index 1, and so on.

my_list = [1, 2, 3]
if len(my_list) > 0:
    index = 2
    if index < len>

Handle Empty Lists: If you expect the list to sometimes be empty, you can add conditional checks to handle this case gracefully.

my_list = []
if len(my_list) > 0:
    # Access list elements safely
    print(my_list[0])
else:
    print("List is empty")

Error Handling: If you're expecting the list to always have elements and encountering this error indicates an unexpected condition, you can use try-except blocks to catch and handle the error.

my_list = []
try:
    # Access list elements
    print(my_list[0])
except IndexError:
    print("Index out of range or list is empty")

What must be done when a list has no rows for assignment to

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