system.runAs gives different result after querying

Question

My class is using with sharing keyword and method has a query on object which system admin only has access.

List<Login__c> recList = [select id, clientId__c, clientsecret__c from login__c];

So in my test class to test for multiple profiles I am using below:

User u = [select id from user where profile.name != 'System Administrator' Limit 1];
system.runAs(u) {
    MainClass.retrieveQuery();
}

I expect above to throw error when method is called as query in that method can only be run succesfully by system admin but it doesnot throw any error.

However, if I pass specific profile name which is not system admin as below, it runs as expected throws an exception "List has no rows for assignment to sObject"

User u = [select id from user where profile.name = 'Integration User' Limit 1];
system.runAs(u) {
    MainClass.retrieveQuery();
}

My another question is how to catch list has no exceptions error. I tried below:

List<Login__c> recList = new List<Login__c>();
try {
    recList = [select id, clientId__c, clientsecret__c from login__c];
} catch(QueryException qe) {
    system.debug('Query exception: '+qe);
} catch(Exception e) {
    system.debug('Exception: '+e);
}

Even though above code throws exception "List has no rows exception" when run by non-system admin profile, this exception is not caught in either catch block.

Answer 1

You only get an error that List has no rows for assignment to SObject if you assign to a single record:

static testmethod void demonstration()
{
    QueryException expectedException;

    Test.startTest();
        try
        {
            User record = [SELECT Id FROM User WHERE Id = null];
        }
        catch (QueryException q)
        {
            expectedException = q;
        }
    Test.stopTest();

    system.assertNotEquals(null, expectedException, 'An exception should be thrown');
}

You are assigning to a list, so an empty query result is not an exception case. Whether you use system.runAs or not has nothing to do with the behavior difference you observe here.