How to override tableview delegate in XCTest

Question

How to write a testcase for this "success" scenario?

if ([tblView.delegate respondsToSelector:@selector(tableView:viewForHeaderInSection:)]) {
         ...
}else{
         ...
}

I have tried by creating the below mock delegate in swift:

class MockTableViewDelegate:NSObject, UITableViewDelegate {

  @objc func tableView(tableView: UITableView, heightForHeaderInSection section: Int) -> CGFloat {
            return 30
        }

        // MARK: Delegates
   @objc func tableView(tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
            return UIView()
        }
}

Code:

mockTableView.delegate=MockTableViewDelegate()  
print("delegate===\(mockTableView.delegate)")

It prints nil. The same mockup I have tried for the datasource and it is returning the datasource obj. Why delegate is returning nil? and how to test this scenario?

Answer 1

Delegates are usually weak references. If you assign your MockTableViewDelegate to a local variable first it should still be alive when used in print. Try the following:

let delegate = MockTableViewDelegate()
mockTableView.delegate = delegate
print("delegate===\(mockTableView.delegate)")
print(delegate)

The fourth line is required to keep the object living for the third line.