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https://github.com/wetransfer/mocker

Mock Alamofire and URLSession requests without touching your code implementation
https://github.com/wetransfer/mocker

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Mock Alamofire and URLSession requests without touching your code implementation

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README 

        


    

























Mocker is a library written in Swift which makes it possible to mock data requests using a custom `URLProtocol`.



- [Features](#features)

- [Requirements](#requirements)

- [Usage](#usage)

    - [Activating the Mocker](#activating-the-mocker)

	    - [Custom URLSessions](#custom-urlsessions)

	    - [Alamofire](#alamofire)

    - [Register Mocks](#register-mocks)

	    - [Create your mocked data](#create-your-mocked-data)

	    - [JSON Requests](#json-requests)

	    - [File extensions](#file-extensions)

	    - [Custom HEAD and GET response](#custom-head-and-get-response)

	    - [Delayed responses](#delayed-responses)

	    - [Redirect responses](#redirect-responses)

	    - [Ignoring URLs](#ignoring-urls)

	    - [Mock callbacks](#mock-callbacks)

    - [Unregister Mocks](#unregister-mocks)

	    - [Clear all registered mocks](#clear-all-registered-mocks)

- [Communication](#communication)

- [Installation](#installation)

- [Release Notes](#release-notes)

- [License](#license)



## Features

_Run all your data request unit tests offline_ 🎉



- [x] Create mocked data requests based on an URL

- [x] Create mocked data requests based on a file extension

- [x] Works with `URLSession` using a custom protocol class

- [x] Supports popular frameworks like `Alamofire`



## Usage



Unit tests are written for the `Mocker` which can help you to see how it works.



### Activating the Mocker

The mocker will automatically be activated for the default URL loading system like `URLSession.shared` after you've registered your first `Mock`. 



##### Custom URLSessions

To make it work with your custom `URLSession`, the `MockingURLProtocol` needs to be registered:



```swift

let configuration = URLSessionConfiguration.default

configuration.protocolClasses = [MockingURLProtocol.self]

let urlSession = URLSession(configuration: configuration)

```



##### Alamofire

Quite similar like registering on a custom `URLSession`.



```swift

let configuration = URLSessionConfiguration.af.default

configuration.protocolClasses = [MockingURLProtocol.self]

let sessionManager = Alamofire.Session(configuration: configuration)

```



### Register Mocks

##### Create your mocked data

It's recommended to create a class with all your mocked data accessible. An example of this can be found in the unit tests of this project:



```swift

public final class MockedData {

    public static let botAvatarImageResponseHead: Data = try! Data(contentsOf: Bundle(for: MockedData.self).url(forResource: "Resources/Responses/bot-avatar-image-head", withExtension: "data")!)

    public static let botAvatarImageFileUrl: URL = Bundle(for: MockedData.self).url(forResource: "wetransfer_bot_avater", withExtension: "png")!

    public static let exampleJSON: URL = Bundle(for: MockedData.self).url(forResource: "Resources/JSON Files/example", withExtension: "json")!

}

```



##### JSON Requests

``` swift

let originalURL = URL(string: "https://www.wetransfer.com/example.json")!

    

let mock = Mock(url: originalURL, contentType: .json, statusCode: 200, data: [

    .get : try! Data(contentsOf: MockedData.exampleJSON) // Data containing the JSON response

])

mock.register()



URLSession.shared.dataTask(with: originalURL) { (data, response, error) in

    guard let data = data, let jsonDictionary = (try? JSONSerialization.jsonObject(with: data, options: [])) as? [String: Any] else {

        return

    }

    

    // jsonDictionary contains your JSON sample file data

    // ..

    

}.resume()

```



##### Empty Responses

``` swift

let originalURL = URL(string: "https://www.wetransfer.com/api/foobar")!

var request = URLRequest(url: originalURL)

request.httpMethod = "PUT"

    

let mock = Mock(request: request, statusCode: 204)

mock.register()



URLSession.shared.dataTask(with: originalURL) { (data, response, error) in

    // ....

}.resume()

```



##### Ignoring the query

Some URLs like authentication URLs contain timestamps or UUIDs in the query. To mock these you can ignore the Query for a certain URL:



``` swift

/// Would transform to "https://www.example.com/api/authentication" for example.

let originalURL = URL(string: "https://www.example.com/api/authentication?oauth_timestamp=151817037")!

    

let mock = Mock(url: originalURL, ignoreQuery: true, contentType: .json, statusCode: 200, data: [

    .get : try! Data(contentsOf: MockedData.exampleJSON) // Data containing the JSON response

])

mock.register()



URLSession.shared.dataTask(with: originalURL) { (data, response, error) in

    guard let data = data, let jsonDictionary = (try? JSONSerialization.jsonObject(with: data, options: [])) as? [String: Any] else {

        return

    }

    

    // jsonDictionary contains your JSON sample file data

    // ..

    

}.resume()

```



##### File extensions

```swift

let imageURL = URL(string: "https://www.wetransfer.com/sample-image.png")!



Mock(fileExtensions: "png", contentType: .imagePNG, statusCode: 200, data: [

    .get: try! Data(contentsOf: MockedData.botAvatarImageFileUrl)

]).register()



URLSession.shared.dataTask(with: imageURL) { (data, response, error) in

    let botAvatarImage: UIImage = UIImage(data: data!)! // This is the image from your resources.

}.resume()

```



##### Custom HEAD and GET response

```swift

let exampleURL = URL(string: "https://www.wetransfer.com/api/endpoint")!



Mock(url: exampleURL, contentType: .json, statusCode: 200, data: [

    .head: try! Data(contentsOf: MockedData.headResponse),

    .get: try! Data(contentsOf: MockedData.exampleJSON)

]).register()



URLSession.shared.dataTask(with: exampleURL) { (data, response, error) in

	// data is your mocked data

}.resume()

```



##### Custom DataType

In addition to the already build in static `DataType` implementations it is possible to create custom ones that will be used as the value to the `Content-Type` header key. 



```swift

let xmlURL = URL(string: "https://www.wetransfer.com/sample-xml.xml")!



Mock(fileExtensions: "png", contentType: .init(name: "xml", headerValue: "text/xml"), statusCode: 200, data: [

    .get: try! Data(contentsOf: MockedData.sampleXML)

]).register()



URLSession.shared.dataTask(with: xmlURL) { (data, response, error) in

    let sampleXML: Data = data // This is the xml from your resources.

}.resume(

```



##### Delayed responses

Sometimes you want to test if the cancellation of requests is working. In that case, the mocked request should not finish immediately and you need a delay. This can be added easily:



```swift

let exampleURL = URL(string: "https://www.wetransfer.com/api/endpoint")!



var mock = Mock(url: exampleURL, contentType: .json, statusCode: 200, data: [

    .head: try! Data(contentsOf: MockedData.headResponse),

    .get: try! Data(contentsOf: MockedData.exampleJSON)

])

mock.delay = DispatchTimeInterval.seconds(5)

mock.register()

```



##### Redirect responses

Sometimes you want to mock short URLs or other redirect URLs. This is possible by saving the response and mocking the redirect location, which can be found inside the response:



```

Date: Tue, 10 Oct 2017 07:28:33 GMT

Location: https://wetransfer.com/redirect

```



By creating a mock for the short URL and the redirect URL, you can mock redirect and test this behavior:



```swift

let urlWhichRedirects: URL = URL(string: "https://we.tl/redirect")!

Mock(url: urlWhichRedirects, contentType: .html, statusCode: 200, data: [.get: try! Data(contentsOf: MockedData.redirectGET)]).register()

Mock(url: URL(string: "https://wetransfer.com/redirect")!, contentType: .json, statusCode: 200, data: [.get: try! Data(contentsOf: MockedData.exampleJSON)]).register()

```



##### Ignoring URLs

As the Mocker catches all URLs by default when registered, you might end up with a `fatalError` thrown in cases you don't need a mocked request. In that case, you can ignore the URL:



```swift

let ignoredURL = URL(string: "https://www.wetransfer.com")!



// Ignore any requests that exactly match the URL

Mocker.ignore(ignoredURL)



// Ignore any requests that match the URL, with any query parameters

// e.g. https://www.wetransfer.com?foo=bar would be ignored

Mocker.ignore(ignoredURL, matchType: .ignoreQuery)



// Ignore any requests that begin with the URL

// e.g. https://www.wetransfer.com/api/v1 would be ignored

Mocker.ignore(ignoredURL, matchType: .prefix)

```



However, if you need the Mocker to catch only mocked URLs and ignore every other URL, you can set the `mode` attribute to `.optin`. 



```swift

Mocker.mode = .optin

```



If you want to set the original mode back, you have just to set it to `.optout`.



```swift

Mocker.mode = .optout

```



##### Mock errors



You can request a `Mock` to return an error, allowing testing of error handling.



```swift

Mock(url: originalURL, contentType: .json, statusCode: 500, data: [.get: Data()],

     requestError: TestExampleError.example).register()



URLSession.shared.dataTask(with: originalURL) { (data, urlresponse, err) in

    XCTAssertNil(data)

    XCTAssertNil(urlresponse)

    XCTAssertNotNil(err)

    if let err = err {

        // there's not a particularly elegant way to verify an instance

        // of an error, but this is a convenient workaround for testing

        // purposes

        XCTAssertEqual("example", String(describing: err))

    }



    expectation.fulfill()

}.resume()

```



##### Mock callbacks

You can register on `Mock` callbacks to make testing easier.



```swift

var mock = Mock(url: request.url!, contentType: .json, statusCode: 200, data: [.post: Data()])

mock.onRequestHandler = OnRequestHandler(httpBodyType: [[String:String]].self, callback: { request, postBodyArguments in

    XCTAssertEqual(request.url, mock.request.url)

    XCTAssertEqual(expectedParameters, postBodyArguments)

    onRequestExpectation.fulfill()

})

mock.completion = {

    endpointIsCalledExpectation.fulfill()

}

mock.register()

```



##### Mock expectations

Instead of setting the `completion` and `onRequest` you can also make use of expectations:



```swift

var mock = Mock(url: url, contentType: .json, statusCode: 200, data: [.get: Data()])

let requestExpectation = expectationForRequestingMock(&mock)

let completionExpectation = expectationForCompletingMock(&mock)

mock.register()



URLSession.shared.dataTask(with: URLRequest(url: url)).resume()



wait(for: [requestExpectation, completionExpectation], timeout: 2.0)

```



### Unregister Mocks

##### Clear all registered mocks

You can clear all registered mocks:



```swift

Mocker.removeAll()

```



## Communication



- If you **found a bug**, open an issue.

- If you **have a feature request**, open an issue.

- If you **want to contribute**, submit a pull request.



## Installation



### Carthage



[Carthage](https://github.com/Carthage/Carthage) is a decentralized dependency manager that builds your dependencies and provides you with binary frameworks.



You can install Carthage with [Homebrew](http://brew.sh/) using the following command:



```bash

$ brew update

$ brew install carthage

```



To integrate Mocker into your Xcode project using Carthage, specify it in your `Cartfile`:



```ogdl

github "WeTransfer/Mocker" ~> 3.0.0

```



Run `carthage update` to build the framework and drag the built `Mocker.framework` into your Xcode project.



### Swift Package Manager



The [Swift Package Manager](https://swift.org/package-manager/) is a tool for managing the distribution of Swift code. It’s integrated with the Swift build system to automate the process of downloading, compiling, and linking dependencies.



#### Manifest File



Add Mocker as a package to your `Package.swift` file and then specify it as a dependency of the Target in which you wish to use it.



```swift

import PackageDescription



let package = Package(

    name: "MyProject",

    platforms: [

       .macOS(.v10_15)

    ],

    dependencies: [

        .package(url: "https://github.com/WeTransfer/Mocker.git", .upToNextMajor(from: "3.0.0"))

    ],

    targets: [

        .target(

            name: "MyProject",

            dependencies: ["Mocker"]),

        .testTarget(

            name: "MyProjectTests",

            dependencies: ["MyProject"]),

    ]

)

```



#### Xcode



To add Mocker as a [dependency](https://developer.apple.com/documentation/xcode/adding_package_dependencies_to_your_app) to your Xcode project, select *File > Swift Packages > Add Package Dependency* and enter the repository URL.



#### Resolving Build Errors

If you get the following error: *cannot find auto-link library XCTest and XCTestSwiftSupport*, set the following property under Build Options from No to Yes.  

ENABLE_TESTING_SEARCH_PATHS to YES



### Manually



If you prefer not to use any of the aforementioned dependency managers, you can integrate Mocker into your project manually.



#### Embedded Framework



- Open up Terminal, `cd` into your top-level project directory, and run the following command "if" your project is not initialized as a git repository:



  ```bash

  $ git init

  ```



- Add Mocker as a git [submodule](http://git-scm.com/docs/git-submodule) by running the following command:



  ```bash

  $ git submodule add https://github.com/WeTransfer/Mocker.git

  ```



- Open the new `Mocker ` folder, and drag the `Mocker.xcodeproj` into the Project Navigator of your application's Xcode project.



    > It should appear nested underneath your application's blue project icon. Whether it is above or below all the other Xcode groups does not matter.



- Select the `Mocker.xcodeproj` in the Project Navigator and verify the deployment target matches that of your application target.

- Next, select your application project in the Project Navigator (blue project icon) to navigate to the target configuration window and select the application target under the "Targets" heading in the sidebar.

- In the tab bar at the top of that window, open the "General" panel.

- Click on the `+` button under the "Embedded Binaries" section.

- Select `Mocker.framework`.

- And that's it!



  > The `Mocker.framework` is automagically added as a target dependency, linked framework and embedded framework in a copy files build phase which is all you need to build on the simulator and a device.



---



## Release Notes



See [CHANGELOG.md](https://github.com/WeTransfer/Mocker/blob/master/Changelog.md) for a list of changes.



## License



Mocker is available under the MIT license. See the LICENSE file for more info.