Rubicon

Swift parser + mock generator + Xcode extension
https://github.com/raptorxcz/Rubicon

Rubicon generates spys, stub, mocks and dummies for protocols. Generating methods for parent protocol is not supported. 

example:

input:

protocol Car {
    var name: String? { get }
    var color: Int { get set }
    
    @MainActor
    func go()
    func load(with stuff: Int, label: String) throws -> Int
    func isFull() -> Bool
    func download() async throws -> [String]
}

output:

spy:

final class CarSpy: Car {
    struct Load {
        let stuff: Int
        let label: String
    }

    var name: String?
    var color: Int
    var loadThrowBlock: () -> Void?
    var loadReturn: Int
    var isFullReturn: Bool
    var downloadThrowBlock: () -> Void?
    var downloadReturn: [String]

    var goCount = 0
    var load = [Load]()
    var isFullCount = 0
    var downloadCount = 0

    init(color: Int, loadReturn: Int, isFullReturn: Bool, downloadReturn: [String]) {
        self.color = color
        self.loadReturn = loadReturn
        self.isFullReturn = isFullReturn
        self.downloadReturn = downloadReturn
    }

    func go() {
        goCount += 1
    }

    func load(with stuff: Int, label: String) throws -> Int {
        let item = Load(stuff: stuff, label: label)
        load.append(item)
        try loadThrowBlock?()
        return loadReturn
    }

    func isFull() -> Bool {
        isFullCount += 1
        return isFullReturn
    }

    func download() async throws -> [String] {
        downloadCount += 1
        try downloadThrowBlock?()
        return downloadReturn
    }
}

stub:

final class CarStub: Car {
    var name: String?
    var color: Int
    var loadThrowBlock: () -> Void?
    var loadReturn: Int
    var isFullReturn: Bool
    var downloadThrowBlock: () -> Void?
    var downloadReturn: [String]

    init(color: Int, loadReturn: Int, isFullReturn: Bool, downloadReturn: [String]) {
        self.color = color
        self.loadReturn = loadReturn
        self.isFullReturn = isFullReturn
        self.downloadReturn = downloadReturn
    }

    func go() {
    }

    func load(with stuff: Int, label: String) throws -> Int {
        try loadThrowBlock?()
        return loadReturn
    }

    func isFull() -> Bool {
        return isFullReturn
    }

    func download() async throws -> [String] {
        try downloadThrowBlock?()
        return downloadReturn
    }
}

dummy:

final class CarDummy: Car {
    var name: String? {
        get {
            fatalError()
        }
    }
    var color: Int {
        get {
            fatalError()
        }
        set {
            fatalError()
        }
    }

    func go() {
        fatalError()
    }

    func load(with stuff: Int, label: String) throws -> Int {
        fatalError()
    }

    func isFull() -> Bool {
        fatalError()
    }

    func download() async throws -> [String] {
        fatalError()
    }
}

usage in tests:

let carSpy = CarSpy()

...

let a1 = carSpy.goCount == 1
let a2 = carSpy.load.count == 1
let a3 = carSpy.load[0].stuff == 2
let a4 = carSpy.load[0].label == "name"

https://github.com/raptorxcz/Rubicon

Xcode extension

Xcode extension can generate test doubles for all or just selected protocols in the current file. The resulting test double can be written to the source file or pasteboard.