Logged in User in Test class

Question

My apex class extracts all the data of a logged in user for an object. how do I replicate this in my Test class. How do I use System.runAs(User)? The test class is running as me when I say in my code to run as test user. How can I overcome this issue?

public string method1(){
    User u = [Select id, name, email from User where id=: UserInfo.getUserId()];
    Account a = [Select id, name from Account where OwnerId =:u.id ];
    //some more code goes here
}

Answer 1

Ultimately, you need to query the user table for the user you want to "run as" and then execute your method.

So something similar to the following.

Class:

public with sharing DataExportClass
{
    public static List<SObject> getData()
    {
        // do some work to get data here and return
    }        
}

Test:

@isTest
private class TestClass
{
    private static void testMyDataExport()
    {
        // setup some test data

        List<user> userForTesting = [SELECT Id FROM User WHERE Id = 'someIdHere' LIMIT 1];

        system.runAs(userForTesting[0]); // normally you want to verify the list has data first as this could cause null exception
        {
            test.startTest();

            // Complete a SOQL call

            test.stopTest();

            // verify the number of records based on your criteria for this specific user
        }
    }
}

Answer 2

First of all, it does not appear necessary to query the User record based on what you have posted. You can change your Account query to just:

public static List<Account> getAllAccounts()
{
    return [SELECT Name FROM Account WHERE OwnerId = :UserInfo.getUserId()];
}

Secondly, you just need to set up a User in your test and then create Account records they own. It will be easier to test this functionality if you have a method that just returns the query results, then put any further processing logic in a different method.

static testMethod void testGetAllAccounts()
{
    User testUser = new User(/*required fields*/);
    insert testUser;

    final Integer recordCount = Limits.getLimitQueries() + 1;
    List<Account> accounts = new List<Account>();
    for (Integer i = 0; i < recordCount; i++)
    {
        accounts.add(new Account(OwnerId=testUser.Id/*, requiredFields*/));
    }
    insert accounts;

    List<Account> allAccounts;
    system.runAs(testUser)
    {
        Test.startTest();
            allAccounts = MyClass.getAllAccounts();
        Test.stopTest();
    }

    system.assertEquals(recordCount, allAccounts.size(),
        'All accounts pertaining to this user should be found);
}

You can add a separate test identical to the above, but set OwnerId=UserInfo.getUserId(), and assertEquals(0, allAccounts.size()). In other words, the query should not find Account records where the OwnerId is not the running user.