sMock-用于单元测试的Swift模拟框架（感谢gMock的想法）

问题

从ObjC / C ++进入Swift世界，编写单元测试时遇到一个问题：缺少用于创建Mock对象的工具。

在编写分解代码时，我们通常将实现细节隐藏在接口（协议）的后面。将对象的组成部分替换为mokami，也非常方便地与其他对象分开检查对象的功能。

谷歌搜索，我在github上找到了几个Swift Mocking框架。但是对我来说，它们在使用中都没有一个清晰明了（出于一个或几个原因）：

• 有依赖性云
• 没有直观的语法
• 代码生成/需要大量辅助代码的手动编写
• 未与XCTest集成（允许潮湿，但未经测试）
• 将许多功能转储到一个框架中（混淆了什么和原因）
• 应该与有限数量的预定义/内置类型一起使用

这种情况对我来说是不愉快的，并且大约一年来，我使用了变通办法和自制的Mokas。
自写的模拟对象很简单，但是它们

• 每次都不同（重新发明轮子）
• 或每次相同（复制粘贴）
• 使用不明显

决断

C ++ gTest / gMock ( Google).
Mock- . , «» ( ) .

gMock, sMock (Swift Mock) gMock.
https://github.com/Alkenso/sMock

sMock:

• mock /
• expectations
• - mock-
• XCTest.framework
• zero-dependency
• pure Swift

()

sMock

• Mock , ( )
• Mock methodCall. "" .

Mocking synchronous method

:

import XCTest
import sMock

//    ,   
protocol HTTPClient {
    func sendRequestSync(_ request: String) -> String
}

//  Mock 
class MockHTTPClient: HTTPClient {
    //   call's mock entity.
    let sendRequestSyncCall = MockMethod<String, String>()

    func sendRequestSync(_ request: String) -> String {
        //  1.    Mock-
        //  2.  non-void   "default"    'Unexpected call' (..     ,   ).
        sendRequestSyncCall.call(request) ?? ""
    }
}

//  ,    
struct Client {
    let httpClient: HTTPClient

    //  ,  HTTP ,    .
    func retrieveRecordsSync() -> [String] {
        let response = httpClient.sendRequestSync("{ action: 'retrieve_records' }")
        return response.split(separator: ";").map(String.init)
    }
}

class ExampleTests: XCTestCase {
    func test_Example() {
        let mock = MockHTTPClient()
        let client = Client(httpClient: mock)

        //     expectation,    'sendRequestSync'  HTTPClient     'request'  "{ action: 'retrieve_records' }".
        //   ,      1     "r1;r2;r3".
        mock.sendRequestSyncCall
            //    expectation (      );
            .expect("Request sent.")
            //  ,   expectation    ,      match
            .match("{ action: 'retrieve_records' }")
            //    ,        (   match)
            .willOnce(
                //  ,    .
                .return("r1;r2;r3"))

        //   expectations,   Client-    .
        let records = client.retrieveRecordsSync()
        XCTAssertEqual(records, ["r1", "r2", "r3"])
    }
}

Mocking synchronous method + mocking asynchonous callback

Mock callback'a, .

//    ,   
protocol HTTPClient {
    func sendRequestSync(_ request: String) -> String
}

//  Mock 
class MockHTTPClient: HTTPClient {
    //   call's mock entity.
    let sendRequestSyncCall = MockMethod<String, String>()

    func sendRequestSync(_ request: String) -> String {
        //  1.    Mock-
        //  2.  non-void   "default"    'Unexpected call' (..     ,   ).
        sendRequestSyncCall.call(request) ?? ""
    }
}

//  ,    
struct Client {
    let httpClient: HTTPClient

    //  ,  HTTP ,    .   
    func retrieveRecordsAsync(completion: @escaping ([String]) -> Void) {
        let response = httpClient.sendRequestSync("{ action: 'retrieve_records' }")
        completion(response.split(separator: ";").map(String.init))
    }
}

class ExampleTests: XCTestCase {
    func test_Example() {
        let mock = MockHTTPClient()
        let client = Client(httpClient: mock)

        //     expectation,    'sendRequestSync'  HTTPClient     'request'  "{ action: 'retrieve_records' }".
        //   ,      1     "r1;r2;r3".
        mock.sendRequestSyncCall
            //    expectation (      );
            .expect("Request sent.")
            //  ,   expectation    ,      match
            .match("{ action: 'retrieve_records' }")
            //    ,        (   match)
            .willOnce(
                //  ,    .
                .return("r1;r2;r3"))

        //    expectation    ( ). 
        //     ,     -  :  'MockClosure' mock entity.
        //     expectation,      1    ( ) ["r1", "r2", "r3"].
        let completionCall = MockClosure<[String], Void>()
        completionCall
            //    expectation (      );
            .expect("Records retrieved.")
            //  ,   expectation    ,      match
            .match(["r1", "r2", "r3"])
            //    ,        (   match).
            //   return value   Void, .return   .
            .willOnce()

        //   expectations,   Client-.
        client.retrieveRecordsAsync(completion: completionCall.asClosure())

        //      expectations (  " "    ).
        sMock.waitForExpectations()
    }
}

Matchers, Actions, Argument capture

sMock (. ):

• Matchers — , .match: .any ( )
• Actions: expectation match'e .return, .
• : expectation .
• : , unexpectedCall

.
.
: , . .

, Swift .
, sMock . .
"testing with Swift"!

Try sMock on github (with SwiftPackageManager)