XCTestSuite+Helper.swift

private class Example: NSObject {
    @objc func example() {}
}

extension XCTestSuite {

    public func addTests<Test: XCTestCase>(
        _ tests: [(String, (Test) -> () -> Void)])
    {
        let method = class_getInstanceMethod(Example.self,
                                             #selector(Example.example))
        guard let methodType = method.map(method_getTypeEncoding) else {
            return
        }
        for (name, execute) in tests {
            let blockA: @convention(block) (Test?,Selector?)->Void = { obj, _ in
                if let obj = obj {
                    execute(obj)()
                }
            }
            let block = unsafeBitCast(blockA, to: AnyObject.self)
            let sel = Selector(name)
            let imp = imp_implementationWithBlock(block)

            class_addMethod(Test.self, sel, imp, methodType)

            self.addTest(Test(selector: sel))
        }
    }
}