I'm not sure the app's threads are suspended like `sleep`, but the code in this gist will pause for a bit before relaunching the app for UI testing.

WaitBeforeRelaunch.swift

func waitAndRelaunch(timeout: TimeInterval = 0) {
    let waitingExpectation = XCTestExpectation(description: "Wait a bit")
    DispatchQueue.main.asyncAfter(deadline: .now() + .seconds(Int(timeout))) {
        waitingExpectation.fulfill()
    }
    self.wait(for: [waitingExpectation], timeout: timeout + 1)
    self.app.relaunch()
}