Cuckoo/Source/MockManager.swift

//
//  MockManager.swift
//  Cuckoo
//
//  Created by Filip Dolnik on 29.05.16.
//  Copyright © 2016 Brightify. All rights reserved.
//

import XCTest

#if !swift(>=4.1)
private extension Array {
    func compactMap<O>(_ transform: (Element) -> O?) -> [O] {
        return self.flatMap(transform)
    }
}
#endif

public class MockManager {
    public static var fail: ((message: String, sourceLocation: SourceLocation)) -> () = { (arg) in let (message, sourceLocation) = arg; XCTFail(message, file: sourceLocation.file, line: sourceLocation.line) }
    private var stubs: [Stub] = []
    private var stubCalls: [StubCall] = []
    private var unverifiedStubCallsIndexes: [Int] = []
    // TODO Add either enum or OptionSet for these behavior modifiers and add proper validation
    private var isSuperclassSpyEnabled = false
    private var isDefaultImplementationEnabled = false
    
    private let hasParent: Bool

    public init(hasParent: Bool) {
        self.hasParent = hasParent
    }

    private func callInternal<IN, OUT>(_ method: String, parameters: IN, escapingParameters: IN, superclassCall: () -> OUT, defaultCall: () -> OUT) -> OUT {
        return try! callThrowsInternal(method, parameters: parameters, escapingParameters: escapingParameters, superclassCall: superclassCall, defaultCall: defaultCall)
    }
    
    private func callThrowsInternal<IN, OUT>(_ method: String, parameters: IN, escapingParameters: IN, superclassCall: () throws -> OUT, defaultCall: () throws -> OUT) throws -> OUT {
        let stubCall = ConcreteStubCall(method: method, parameters: escapingParameters)
        stubCalls.append(stubCall)
        unverifiedStubCallsIndexes.append(stubCalls.count - 1)
        
        if let stub = (stubs.filter { $0.method == method }.compactMap { $0 as? ConcreteStub<IN, OUT> }.filter { $0.parameterMatchers.reduce(true) { $0 && $1.matches(parameters) } }.first) {
            if let action = stub.actions.first {
                if stub.actions.count > 1 {
                    // Bug in Swift, this expression resolves as uncalled function
                    _ = stub.actions.removeFirst()
                }
                switch action {
                case .callImplementation(let implementation):
                    return try implementation(parameters)
                case .returnValue(let value):
                    return value
                case .throwError(let error):
                    throw error
                case .callRealImplementation where hasParent:
                    return try superclassCall()
                default:
                    failAndCrash("No real implementation found for method `\(method)`. This is probably caused  by stubbed object being a mock of a protocol.")
                }
            } else {
                failAndCrash("Stubbing of method `\(method)` using parameters \(parameters) wasn't finished (missing thenReturn()).")
            }
        } else if isSuperclassSpyEnabled {
            return try superclassCall()
        } else if isDefaultImplementationEnabled {
            return try defaultCall()
        } else {
            failAndCrash("No stub for method `\(method)` using parameters \(parameters).")
        }
    }
    
    public func createStub<MOCK: ClassMock, IN, OUT>(for _: MOCK.Type, method: String, parameterMatchers: [ParameterMatcher<IN>]) -> ClassConcreteStub<IN, OUT> {
        let stub = ClassConcreteStub<IN, OUT>(method: method, parameterMatchers: parameterMatchers)
        stubs.insert(stub, at: 0)
        return stub
    }

    public func createStub<MOCK: ProtocolMock, IN, OUT>(for _: MOCK.Type, method: String, parameterMatchers: [ParameterMatcher<IN>]) -> ConcreteStub<IN, OUT> {
        let stub = ConcreteStub<IN, OUT>(method: method, parameterMatchers: parameterMatchers)
        stubs.insert(stub, at: 0)
        return stub
    }
    
    public func verify<IN, OUT>(_ method: String, callMatcher: CallMatcher, parameterMatchers: [ParameterMatcher<IN>], sourceLocation: SourceLocation) -> __DoNotUse<IN, OUT> {
        var calls: [StubCall] = []
        var indexesToRemove: [Int] = []
        for (i, stubCall) in stubCalls.enumerated() {
            if let stubCall = stubCall as? ConcreteStubCall<IN> , (parameterMatchers.reduce(stubCall.method == method) { $0 && $1.matches(stubCall.parameters) }) {
                calls.append(stubCall)
                indexesToRemove.append(i)
            }
        }
        unverifiedStubCallsIndexes = unverifiedStubCallsIndexes.filter { !indexesToRemove.contains($0) }
        
        if callMatcher.matches(calls) == false {
            let message = "Wanted \(callMatcher.name) but \(calls.count == 0 ? "not invoked" : "invoked \(calls.count) times")."
            MockManager.fail((message, sourceLocation))
        }
        return __DoNotUse()
    }

    public func enableSuperclassSpy() {
        guard stubCalls.isEmpty else {
            failAndCrash("Enabling superclass spy is not allowed after stubbing! Please do that right after creating the mock.")
        }
        guard !isDefaultImplementationEnabled else {
            failAndCrash("Enabling superclass spy is not allowed with the default stub implementation enabled.")
        }

        isSuperclassSpyEnabled = true
    }

    public func enableDefaultStubImplementation() {
        guard stubCalls.isEmpty else {
            failAndCrash("Enabling default stub implementation is not allowed after stubbing! Please do that right after creating the mock.")
        }
        guard !isSuperclassSpyEnabled else {
            failAndCrash("Enabling default stub implementation is not allowed with superclass spy enabled.")
        }

        isDefaultImplementationEnabled = true
    }
    
    func reset() {
        clearStubs()
        clearInvocations()
    }
    
    func clearStubs() {
        stubs.removeAll()
    }
    
    func clearInvocations() {
        stubCalls.removeAll()
        unverifiedStubCallsIndexes.removeAll()
    }
    
    func verifyNoMoreInteractions(_ sourceLocation: SourceLocation) {
        if unverifiedStubCallsIndexes.isEmpty == false {
            let unverifiedCalls = unverifiedStubCallsIndexes.map { stubCalls[$0] }.map { call in
                    if let bracketIndex = call.method.range(of: "(")?.lowerBound {
                        let name = call.method[..<bracketIndex]
                        return name + call.parametersAsString
                    } else {
                        if call.method.hasSuffix("#set") {
                            return call.method + call.parametersAsString
                        } else {
                            return call.method
                        }
                    }
                }.enumerated().map { "\($0 + 1). " + $1 }.joined(separator: "\n")
            let message = "No more interactions wanted but some found:\n"
            MockManager.fail((message + unverifiedCalls, sourceLocation))
        }
    }

    private func failAndCrash(_ message: String, file: StaticString = #file, line: UInt = #line) -> Never  {
        MockManager.fail((message, (file, line)))

        #if _runtime(_ObjC)
            NSException(name: .internalInconsistencyException, reason:message, userInfo: nil).raise()
        #endif

        fatalError(message)
    }
}

extension MockManager {
    public static func callOrCrash<T, OUT>(_ value: T?, call: (T) throws -> OUT) rethrows -> OUT {
        guard let value = value else { return crashOnProtocolSuperclassCall() }
        return try call(value)
    }

    public static func crashOnProtocolSuperclassCall<OUT>() -> OUT {
        fatalError("This should never get called. If it does, please report an issue to Cuckoo repository.")
    }
}

extension MockManager {
    public func getter<T>(_ property: String, superclassCall: @autoclosure () -> T, defaultCall: @autoclosure () -> T) -> T {
        return call(getterName(property), parameters: Void(), escapingParameters: Void(), superclassCall: superclassCall, defaultCall: defaultCall())
    }

    public func setter<T>(_ property: String, value: T, superclassCall: @autoclosure () -> Void, defaultCall: @autoclosure () -> Void) {
        return call(setterName(property), parameters: value, escapingParameters: value, superclassCall: superclassCall, defaultCall: defaultCall())
    }
}

extension MockManager {
    public func call<IN, OUT>(_ method: String, parameters: IN, escapingParameters: IN, superclassCall: @autoclosure () -> OUT, defaultCall: @autoclosure () -> OUT) -> OUT {
        return callInternal(method, parameters: parameters, escapingParameters: escapingParameters, superclassCall: superclassCall, defaultCall: defaultCall)
    }
}

extension MockManager {
    public func callThrows<IN, OUT>(_ method: String, parameters: IN, escapingParameters: IN, superclassCall: @autoclosure () throws -> OUT, defaultCall: @autoclosure () throws -> OUT) throws -> OUT {
        return try callThrowsInternal(method, parameters: parameters, escapingParameters: escapingParameters, superclassCall: superclassCall, defaultCall: defaultCall)
    }
}