How to wait in a XCTest for T seconds without timeout error?

Question

I want to delay progression of a test for T seconds, without generating a timeout.

First I tried the obvious:

sleep(5)
XCTAssert(<test if state is correct after this delay>)

But that failed.

Then I tried:

let promise = expectation(description: "Just wait 5 seconds")
waitForExpectations(timeout: 5) { (error) in
    promise.fulfill()

    XCTAssert(<test if state is correct after this delay>)
}

My XCTAssert() now succeeded. But waitForExpectations() failed with a timeout.

This is according to the documentation of XCTest wait functions saying:

Timeout is always treated as a test failure.

What are my options?

Answer 1

You can use XCTWaiter.wait functions.

For example:

let exp = expectation(description: "Test after 5 seconds")
let result = XCTWaiter.wait(for: [exp], timeout: 5.0)
if result == XCTWaiter.Result.timedOut {
    XCTAssert(<test if state is correct after this delay>)
} else {
    XCTFail("Delay interrupted")
}