Mocker is a library written in Swift which makes it possible to mock data requests using a custom URLProtocol
.
Run all your data request unit tests offline π
- Create mocked data requests based on an URL
- Create mocked data requests based on a file extension
- Works with
URLSession
using a custom protocol class - Supports popular frameworks like
Alamofire
Unit tests are written for the Mocker
which can help you to see how it works.
The mocker will automatically be activated for the default URL loading system like URLSession.shared
after you've registered your first Mock
.
To make it work with your custom URLSession
, the MockingURLProtocol
needs to be registered:
let configuration = URLSessionConfiguration.default
configuration.protocolClasses = [MockingURLProtocol.self]
let urlSession = URLSession(configuration: configuration)
Quite similar like registering on a custom URLSession
.
let configuration = URLSessionConfiguration.af.default
configuration.protocolClasses = [MockingURLProtocol.self]
let sessionManager = Alamofire.Session(configuration: configuration)
It's recommend to create a class with all your mocked data accessible. An example of this can be found in the unit tests of this project:
public final class MockedData {
public static let botAvatarImageResponseHead: Data = Bundle(for: MockedData.self).url(forResource: "Resources/Responses/bot-avatar-image-head", withExtension: "data")!.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")!
}
let originalURL = URL(string: "https://www.wetransfer.com/example.json")!
let mock = Mock(url: originalURL, dataType: .json, statusCode: 200, data: [
.get : MockedData.exampleJSON.data // 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()
Some URLs like authentication URLs contain timestamps or UUIDs in the query. To mock these you can ignore the Query for a certain URL:
/// 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, dataType: .json, statusCode: 200, data: [
.get : MockedData.exampleJSON.data // 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()
let imageURL = URL(string: "https://www.wetransfer.com/sample-image.png")!
Mock(fileExtensions: "png", dataType: .imagePNG, statusCode: 200, data: [
.get: MockedData.botAvatarImageFileUrl.data
]).register()
URLSession.shared.dataTask(with: imageURL) { (data, response, error) in
let botAvatarImage: UIImage = UIImage(data: data!)! // This is the image from your resources.
}.resume()
let exampleURL = URL(string: "https://www.wetransfer.com/api/endpoint")!
Mock(url: exampleURL, dataType: .json, statusCode: 200, data: [
.head: MockedData.headResponse.data,
.get: MockedData.exampleJSON.data
]).register()
URLSession.shared.dataTask(with: exampleURL) { (data, response, error) in
// data is your mocked data
}.resume()
Sometimes you want to test if cancellation of requests is working. In that case, the mocked request should not finished directly and you need an delay. This can be added easily:
let exampleURL = URL(string: "https://www.wetransfer.com/api/endpoint")!
var mock = Mock(url: exampleURL, dataType: .json, statusCode: 200, data: [
.head: MockedData.headResponse.data,
.get: MockedData.exampleJSON.data
])
mock.delay = DispatchTimeInterval.seconds(5)
mock.register()
Sometimes you want to mock short URLs or other redirect URLs. This is possible by saving the response and mock 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 behaviour:
let urlWhichRedirects: URL = URL(string: "https://we.tl/redirect")!
Mock(url: urlWhichRedirects, dataType: .html, statusCode: 200, data: [.get: MockedData.redirectGET.data]).register()
Mock(url: URL(string: "https://wetransfer.com/redirect")!, dataType: .json, statusCode: 200, data: [.get: MockedData.exampleJSON.data]).register()
As the Mocker catches all URLs 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:
let ignoredURL = URL(string: "www.wetransfer.com")!
Mocker.ignore(ignoredURL)
You can request a Mock
to return an error, allowing testing of error handling.
Mock(url: originalURL, dataType: .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()
You can register on Mock
callbacks to make testing easier.
var mock = Mock(url: request.url!, dataType: .json, statusCode: 200, data: [.post: Data()])
mock.onRequest = { request, postBodyArguments in
XCTAssertEqual(request.url, mock.request.url)
XCTAssertEqual(expectedParameters, postBodyArguments as? [String: String])
onRequestExpectation.fulfill()
}
mock.completion = {
endpointIsCalledExpectation.fulfill()
}
mock.register()
Instead of setting the completion
and onRequest
you can also make use of expectations:
var mock = Mock(url: url, dataType: .json, statusCode: 200, data: [.get: Data()])
let requestExpectation = expectationForCompletingMock(&mock)
let completionExpectation = expectationForCompletingMock(&mock)
mock.register()
URLSession.shared.dataTask(with: URLRequest(url: url)).resume()
wait(for: [requestExpectation, completionExpectation], timeout: 2.0)
- 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.
CocoaPods is a dependency manager for Cocoa projects. You can install it with the following command:
$ gem install cocoapods
To integrate Mocker into your Xcode project using CocoaPods, specify it in your Podfile
:
source 'https://github.com/CocoaPods/Specs.git'
platform :ios, '10.0'
use_frameworks!
target '<Your Target Name>' do
pod 'Mocker', '~> 2.3.0'
end
Then, run the following command:
$ pod install
Carthage is a decentralized dependency manager that builds your dependencies and provides you with binary frameworks.
You can install Carthage with Homebrew using the following command:
$ brew update
$ brew install carthage
To integrate Mocker into your Xcode project using Carthage, specify it in your Cartfile
:
github "WeTransfer/Mocker" ~> 2.3.0
Run carthage update
to build the framework and drag the built Mocker.framework
into your Xcode project.
The Swift Package Manager is a tool for managing the distribution of Swift code. Itβs integrated with the Swift build system to automate the process of downloading, compiling, and linking dependencies.
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.
import PackageDescription
let package = Package(
name: "MyProject",
platforms: [
.macOS(.v10_15)
],
dependencies: [
.package(url: "https://github.com/WeTransfer/Mocker.git", .upToNextMajor(from: "2.3.0"))
],
targets: [
.target(
name: "MyProject",
dependencies: ["Mocker"]),
.testTarget(
name: "MyProjectTests",
dependencies: ["MyProject"]),
]
)
To add Mocker as a dependency to your Xcode project, select File > Swift Packages > Add Package Dependency and enter the repository URL.
If you prefer not to use any of the aforementioned dependency managers, you can integrate Mocker into your project manually.
-
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:$ git init
-
Add Mocker as a git submodule by running the following command:
$ git submodule add https://github.com/WeTransfer/Mocker.git
-
Open the new
Mocker
folder, and drag theMocker.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.
See CHANGELOG.md for a list of changes.
Mocker is available under the MIT license. See the LICENSE file for more info.