ContentHandlerTests.swift

class PresenterMock: Mock<PresenterMock.Functions>, Presenter {
    enum Functions: FunctionName {
        case present = "present(title:description:)"
    }
        
    func present(title: String, description: String) { log(parameters: (title, description)) }
}
 
/* In the ContentHandlerTests */

func testHandlePositiveInput() {
    handler.handleInput(5)
        
    let function = presenterMock.calls(with: .present)
    XCTAssertNotNil(function)
    XCTAssertEqual(function?.numberOfCalls, 1)
        
    let parameters = function?.calls.last as? (String, String)
    XCTAssertEqual(parameters?.0, "Positive")
    XCTAssertEqual(parameters?.1, "Great input")
}