Test class for a batch - variable does not exist

Question

I wrote a test class for my batchable class. It works great but I want to limit the query of the test class only to the test object I have created.

So I have this inside my test method:

String query = 'SELECT Id, Name, ShipmentQuantity__c, CurrentQuantity__c FROM Stock__c WHERE Id =: ' + testStock.Id;

And then my test.StartTest():

system.test.startTest();
Database.executeBatch(new IndependentBatch(query));
system.test.stopTest();

The error I get is

"System.QueryException: Variable does not exist: a0236000001bOXdAAM".

Obviously it sees the ID but I don't understand what the error means. If I erase the Where Id =: ' + testStock.Id; the test runs like a charm.

Answer 1

You're mixing up your variables. When you use merge syntax in SOQL, you must use the name of an existing variable in your scope. So if you had a variable called stockId, you could use: 'WHERE Id = :stockId'. You can't do any cross-references, though, so stock.Id cannot be merged in.

However, if you use 'WHERE Id = :'' + stockId, you get a resulting query string of 'WHERE Id = :a0236000001bOXdAAM'. Since you do not have a variable called a0236000001bOXdAAM, you get an error.

Answer 2

When you use : in a query, it causes the runtime engine to attempt to resolve a variable in the local scope. In other words, it's looking for a variable named a0236000001bOXdAAM. This binding occurs when Database.query, Database.queryCount, or Database.search is called with string parameter.

Instead, you'll need to quote the value correctly:

String query = 'SELECT Id, Name, ShipmentQuantity__c, CurrentQuantity__c FROM Stock__c WHERE Id = \'' + testStock.Id + '\'';