Testing a method that has a `try-catch` inside it using XCTest

I'm trying to test a method with a

try-catch

Let's say we have this:

class Foo
{
     func fetchData(request: NSFetchRequest) -> [AnyObject]?
     {
          var data: [AnyObject]? = nil
          do {
               data = try context.executeFetchRequest(request)

          } catch {}      
          return data   
     }

     func fetchData(entity: String, predicate: NSPredicate?) -> [AnyObject]?
     {
          let entity = NSEntityDescription.entityForName(entity, inManagedObjectContext: context)
          let request = NSFetchRequest()
          request.entity = entity
          request.predicate = predicate
          return fetchData(request)
     }
}

class SampleTests: XCTestCase
{
     // Assume that entity 'Employee' does not exist in the core data model.
     func testFetchDataWithNonExistingEntity()
     {
          let foo = Foo()
          let predicate = NSPredicate(format: "id == %i", 22345)
          let data = foo.fetchData("Employee", predicate: predicate)
          XCTAssertNil(data, "Data should be nil.")
     }
}

The test stops at

data = try context.executeFetchRequest(request)