func testAssociation() {
        class Holder {}
        class Association {}

        var associationHolder: Holder? = Holder()
        var strongReferenceAssociation: Association? = Association()
        weak var weakReferenceAssociation: Association? = strongReferenceAssociation
        var associationKey = "key"

        objc_setAssociatedObject(associationHolder!, &associationKey, strongReferenceAssociation!, .OBJC_ASSOCIATION_RETAIN)

        weak var retrievedAssociation = objc_getAssociatedObject(associationHolder, &associationKey) as? Association
        XCTAssertTrue(strongReferenceAssociation! === retrievedAssociation!)

        strongReferenceAssociation = nil
        associationHolder = nil

        XCTAssertTrue(weakReferenceAssociation === .none)
    }