Kdan

/// The base class for all mock classes.
class Mock: MockType {
    /// The log containing function call information.
    let log = FunctionLogger()
}

Kdan

protocol MockType {
    /// The log storing function calls.
    var log: FunctionLogger { get }
}

extension MockType {
    /// A Bool indicating if the class has received any function calls.
    var hasReceivedCalls: Bool { log.hasReceivedCalls }

    /// Retrieve the potential calls for a given function name.

Kdan

/// A `FunctionCall` corresponds to the trigger of a function.
struct FunctionCall: Hashable {
    /// The name of the function
    let name: String
    /// The parameters sent to the function.
    let parameters: [Any?]
    /// The number of times the function has been called.
    let calls: Int

    static func == (lhs: FunctionCall, rhs: FunctionCall) -> Bool {

Kdan

typealias FunctionName = String

class FunctionLogger<T: RawRepresentable> where T.RawValue == FunctionName {
    /// A flag indicating if the class has received any function calls.
    var hasReceivedCalls: Bool { !functionCalls.isEmpty }
    /// The function calls.
    private var functionCalls: [T.RawValue: FunctionCall] = .init()

    /// Retrieve the potential calls for a given function name.
    /// - Parameters:

Kdan

/// The name of a function, used to look up calls on the `Mock` class.
protocol FunctionName {
    /// The raw value of the function name.
    var rawValue: String { get }
}

Kdan

class ConcreteBTests: XCTestCase {
    /// The testable `B` class.
    private var b: ConcreteB!
    /// The mocked `C` class injected to `b`.
    private var c: CMock!
    
    override func setUp() {
        super.setUp()
        c = CMock()
        b = ConcreteB(c: c)

Kdan

class ATests: XCTestCase {
    /// The testable `A` class.
    private var a: A!
    /// The mocked `B` class injected to `a`.
    private var b: BMock!
    
    override func setUp() {
        super.setUp()
        b = BMock()
        a = A(b: b)

Kdan

class BMock: B {
    /// The mocked response being returned by the `validateAnswer()` function.
    var validateAnswerResponse = true

    func validateAnswer() -> Bool { validateAnswerResponse }
}

class CMock: C {
    /// Mutable variable can be changed during the test.
    var number = 42

Kdan

class A {
    /// A `Bool` indicating if we have the answer to the universe.
    private(set) var hasAnswer = false
    /// The instance of B we are using to check if we have the answer.
    private let b: B
    
    init(b: B) {
        self.b = b
    }

Kdan

class A {
    /// A `Bool` indicating if we have the answer to the universe.
    private(set) var hasAnswer = false
    /// The instance of B we are using to check if we have the answer.
    private let b: B
    
    init(b: B) {
        self.b = b
    }