completionDealloc.swift

func testCallbackIsNotCalledAfterCancel() {
    // Arrange
    let sut = MasterClass()
    // Act
    let tokenMarker = weaklyScoped(NSObject()) { marker in
        sut.start {
            // keep a strong reference to a marker
            _ = marker
        }
        // cancel should clear start's completion
        sut.cancel()
    }
    //Assert
    XCTAssertNil(tokenMarker)
}

func testStartedMasterDeallocates() {
    // Act
    let weakSut = weaklyScoped(MasterClass()) { sut in
        sut.start { }
    }
    // Assert
    XCTAssertNil(weakSut)
}