Writing checks utilizing XCTVapor
In my earlier article I confirmed you tips on how to construct a sort protected RESTful API utilizing Vapor. This time we will prolong that undertaking a bit and write some checks utilizing the Vapor testing instrument to find the underlying points within the API layer. First we will use XCTVapor library, then we migrate to a light-weight declarative testing framework (Spec) constructed on prime of that.
Earlier than we begin testing our software, we’ve to ensure that if the app runs in testing mode we register an inMemory database as an alternative of our native SQLite file. We will merely alter the configuration and test the atmosphere and set the db driver based mostly on it.
import Vapor
import Fluent
import FluentSQLiteDriver
public func configure(_ app: Utility) throws {
if app.atmosphere == .testing {
app.databases.use(.sqlite(.reminiscence), as: .sqlite, isDefault: true)
}
else {
app.databases.use(.sqlite(.file("Sources/db.sqlite")), as: .sqlite)
}
app.migrations.add(TodoMigration())
attempt app.autoMigrate().wait()
attempt TodoRouter().boot(routes: app.routes)
}
Now we’re able to create our very first unit check utilizing the XCTVapor testing framework. The official docs are brief, however fairly helpful to be taught in regards to the fundamentals of testing Vapor endpoints. Sadly it will not let you know a lot about testing web sites or advanced API calls. ✅
We’ll make a easy check that checks the return sort for our Todo checklist endpoint.
@testable import App
import TodoApi
import Fluent
import XCTVapor
remaining class AppTests: XCTestCase {
func testTodoList() throws {
let app = Utility(.testing)
defer { app.shutdown() }
attempt configure(app)
attempt app.check(.GET, "/todos/", afterResponse: { res in
XCTAssertEqual(res.standing, .okay)
XCTAssertEqual(res.headers.contentType, .json)
_ = attempt res.content material.decode(Web page<TodoListObject>.self)
})
}
}
<swift>
<p>As you may see first we setup & configure our software, then we ship a GET request to the /todos/ endpoint. After we've a response we are able to test the standing code, the content material sort and we are able to attempt to decode the response physique as a sound paginated todo checklist merchandise object.</p>
<p>This check case was fairly easy, now let's write a brand new unit check for the todo merchandise creation.</p>
<swift>
@testable import App
import TodoApi
import Fluent
import XCTVapor
remaining class AppTests: XCTestCase {
func testCreateTodo() throws {
let app = Utility(.testing)
defer { app.shutdown() }
attempt configure(app)
let title = "Write a todo tutorial"
attempt app.check(.POST, "/todos/", beforeRequest: { req in
let enter = TodoCreateObject(title: title)
attempt req.content material.encode(enter)
}, afterResponse: { res in
XCTAssertEqual(res.standing, .created)
let todo = attempt res.content material.decode(TodoGetObject.self)
XCTAssertEqual(todo.title, title)
XCTAssertEqual(todo.accomplished, false)
XCTAssertEqual(todo.order, nil)
})
}
}
This time we might wish to submit a brand new TodoCreateObject as a POST knowledge, happily XCTVapor might help us with the beforeRequest block. We will merely encode the enter object as a content material, then within the response handler we are able to test the HTTP standing code (it needs to be created) decode the anticipated response object (TodoGetObject) and validate the sector values.
I additionally up to date the TodoCreateObject, because it doesn’t make an excessive amount of sense to have an optionally available Bool area and we are able to use a default nil worth for the customized order. 🤓
public struct TodoCreateObject: Codable {
public let title: String
public let accomplished: Bool
public let order: Int?
public init(title: String, accomplished: Bool = false, order: Int? = nil) {
self.title = title
self.accomplished = accomplished
self.order = order
}
}
The check will nonetheless fail, as a result of we’re returning an .okay standing as an alternative of a .created worth. We will simply repair this within the create technique of the TodoController Swift file.
import Vapor
import Fluent
import TodoApi
struct TodoController {
func create(req: Request) throws -> EventLoopFuture<Response> {
let enter = attempt req.content material.decode(TodoCreateObject.self)
let todo = TodoModel()
todo.create(enter)
return todo
.create(on: req.db)
.map { todo.mapGet() }
.encodeResponse(standing: .created, for: req)
}
}
Now we must always attempt to create an invalid todo merchandise and see what occurs…
func testCreateInvalidTodo() throws {
let app = Utility(.testing)
defer { app.shutdown() }
attempt configure(app)
let title = ""
attempt app.check(.POST, "/todos/", beforeRequest: { req in
let enter = TodoCreateObject(title: title)
attempt req.content material.encode(enter)
}, afterResponse: { res in
XCTAssertEqual(res.standing, .created)
let todo = attempt res.content material.decode(TodoGetObject.self)
XCTAssertEqual(todo.title, title)
XCTAssertEqual(todo.accomplished, false)
XCTAssertEqual(todo.order, nil)
})
}
Effectively, that is dangerous, we should not have the ability to create a todo merchandise with no title. We might use the built-in validation API to test person enter, however truthfully talking that is not the very best strategy.
My concern with validation is that to begin with you may’t return customized error messages and the opposite principal cause is that validation in Vapor isn’t async by default. Finally you will face a state of affairs when that you must validate an object based mostly on a db name, then you may’t match that a part of the article validation course of into different non-async area validation. IMHO, this needs to be unified. 🥲
Fort the sake of simplicity we will begin with a customized validation technique, this time with none async logic concerned, afterward I am going to present you tips on how to construct a generic validation & error reporting mechanism to your JSON-based RESTful API.
import Vapor
import TodoApi
extension TodoModel {
func create(_ enter: TodoCreateObject) {
title = enter.title
accomplished = enter.accomplished
order = enter.order
}
static func validateCreate(_ enter: TodoCreateObject) throws {
guard !enter.title.isEmpty else {
throw Abort(.badRequest, cause: "Title is required")
}
}
}
Within the create controller we are able to merely name the throwing validateCreate perform, if one thing goes incorrect the Abort error shall be returned as a response. Additionally it is attainable to make use of an async technique (return with an EventLoopFuture) then await (flatMap) the decision and return our newly created todo if the whole lot was fantastic.
func create(req: Request) throws -> EventLoopFuture<Response> {
let enter = attempt req.content material.decode(TodoCreateObject.self)
attempt TodoModel.validateCreate(enter)
let todo = TodoModel()
todo.create(enter)
return todo
.create(on: req.db)
.map { todo.mapGet() }
.encodeResponse(standing: .created, for: req)
}
The very last thing that we’ve to do is to replace our check case and test for an error response.
struct ErrorResponse: Content material {
let error: Bool
let cause: String
}
func testCreateInvalidTodo() throws {
let app = Utility(.testing)
defer { app.shutdown() }
attempt configure(app)
attempt app.check(.POST, "/todos/", beforeRequest: { req in
let enter = TodoCreateObject(title: "")
attempt req.content material.encode(enter)
}, afterResponse: { res in
XCTAssertEqual(res.standing, .badRequest)
let error = attempt res.content material.decode(ErrorResponse.self)
XCTAssertEqual(error.cause, "Title is required")
})
}
Writing checks is an effective way to debug our server facet Swift code and double test our API endpoints. My solely concern with this strategy is that the code is not an excessive amount of self-explaining.
Declarative unit checks utilizing Spec
XCTVapor and all the check framework works simply nice, however I had a small downside with it. In case you ever labored with JavaScript or TypeScript you might need heard in regards to the SuperTest library. This little npm bundle offers us a declarative syntactical sugar for testing HTTP requests, which I favored approach an excessive amount of to return to common XCTVapor-based check instances.
That is the explanation why I’ve created the Spec “micro-framework”, which is actually one file with with an additional skinny layer round Vapor’s unit testing framework to supply a declarative API. Let me present you the way this works in apply, utilizing a real-world instance. 🙃
import PackageDescription
let bundle = Package deal(
title: "myProject",
platforms: [
.macOS(.v10_15)
],
merchandise: [
.library(name: "TodoApi", targets: ["TodoApi"]),
],
dependencies: [
.package(url: "https://github.com/vapor/vapor", from: "4.44.0"),
.package(url: "https://github.com/vapor/fluent", from: "4.0.0"),
.package(url: "https://github.com/vapor/fluent-sqlite-driver", from: "4.0.0"),
.package(url: "https://github.com/binarybirds/spec", from: "1.0.0"),
],
targets: [
.target(name: "TodoApi"),
.target(
name: "App",
dependencies: [
.product(name: "Fluent", package: "fluent"),
.product(name: "FluentSQLiteDriver", package: "fluent-sqlite-driver"),
.product(name: "Vapor", package: "vapor"),
.target(name: "TodoApi")
],
swiftSettings: [
.unsafeFlags(["-cross-module-optimization"], .when(configuration: .launch))
]
),
.goal(title: "Run", dependencies: [.target(name: "App")]),
.testTarget(title: "AppTests", dependencies: [
.target(name: "App"),
.product(name: "XCTVapor", package: "vapor"),
.product(name: "Spec", package: "spec"),
])
]
)
We had some expectations for the earlier calls, proper? How ought to we check the replace todo endpoint? Effectively, we are able to create a brand new merchandise, then replace it and test if the outcomes are legitimate.
import Spec
func testUpdateTodo() throws {
let app = Utility(.testing)
defer { app.shutdown() }
attempt configure(app)
var existingTodo: TodoGetObject?
attempt app
.describe("A legitimate todo object ought to exists after creation")
.publish("/todos/")
.physique(TodoCreateObject(title: "pattern"))
.count on(.created)
.count on(.json)
.count on(TodoGetObject.self) { existingTodo = $0 }
.check()
XCTAssertNotNil(existingTodo)
let updatedTitle = "Merchandise is finished"
attempt app
.describe("Todo needs to be up to date")
.put("/todos/" + existingTodo!.id.uuidString)
.physique(TodoUpdateObject(title: updatedTitle, accomplished: true, order: 2))
.count on(.okay)
.count on(.json)
.count on(TodoGetObject.self) { todo in
XCTAssertEqual(todo.title, updatedTitle)
XCTAssertTrue(todo.accomplished)
XCTAssertEqual(todo.order, 2)
}
.check()
}
The very first a part of the code expects that we have been in a position to create a todo object, it’s the very same create expectation as we used to write down with the assistance of the XCTVapor framework.
IMHO the general code high quality is approach higher than it was within the earlier instance. We described the check situation then we set our expectations and eventually we run our check. With this format it is going to be extra simple to grasp check instances. In case you examine the 2 variations the create case the second is trivial to grasp, however within the first one you truly should take a deeper have a look at every line to grasp what is going on on.
Okay, yet one more check earlier than we cease, let me present you tips on how to describe the delete endpoint. We’ll refactor our code a bit, since there are some duplications already.
@testable import App
import TodoApi
import Fluent
import Spec
remaining class AppTests: XCTestCase {
non-public struct ErrorResponse: Content material {
let error: Bool
let cause: String
}
@discardableResult
non-public func createTodo(app: Utility, enter: TodoCreateObject) throws -> TodoGetObject {
var existingTodo: TodoGetObject?
attempt app
.describe("A legitimate todo object ought to exists after creation")
.publish("/todos/")
.physique(enter)
.count on(.created)
.count on(.json)
.count on(TodoGetObject.self) { existingTodo = $0 }
.check()
XCTAssertNotNil(existingTodo)
return existingTodo!
}
func testTodoList() throws {
let app = Utility(.testing)
defer { app.shutdown() }
attempt configure(app)
attempt app
.describe("A legitimate todo checklist web page needs to be returned.")
.get("/todos/")
.count on(.okay)
.count on(.json)
.count on(Web page<TodoListObject>.self)
.check()
}
func testCreateTodo() throws {
let app = Utility(.testing)
defer { app.shutdown() }
attempt configure(app)
attempt createTodo(app: app, enter: TodoCreateObject(title: "Write a todo tutorial"))
}
func testCreateInvalidTodo() throws {
let app = Utility(.testing)
defer { app.shutdown() }
attempt configure(app)
attempt app
.describe("An invalid title response needs to be returned")
.publish("/todos/")
.physique(TodoCreateObject(title: ""))
.count on(.badRequest)
.count on(.json)
.count on(ErrorResponse.self) { error in
XCTAssertEqual(error.cause, "Title is required")
}
.check()
}
func testUpdateTodo() throws {
let app = Utility(.testing)
defer { app.shutdown() }
attempt configure(app)
let todo: TodoGetObject? = attempt createTodo(app: app, enter: TodoCreateObject(title: "Write a todo tutorial"))
let updatedTitle = "Merchandise is finished"
attempt app
.describe("Todo needs to be up to date")
.put("/todos/" + todo!.id.uuidString)
.count on(.okay)
.count on(.json)
.physique(TodoUpdateObject(title: updatedTitle, accomplished: true, order: 2))
.count on(TodoGetObject.self) { todo in
XCTAssertEqual(todo.title, updatedTitle)
XCTAssertTrue(todo.accomplished)
XCTAssertEqual(todo.order, 2)
}
.check()
}
func testDeleteTodo() throws {
let app = Utility(.testing)
defer { app.shutdown() }
attempt configure(app)
let todo: TodoGetObject? = attempt createTodo(app: app, enter: TodoCreateObject(title: "Write a todo tutorial"))
attempt app
.describe("Todo needs to be up to date")
.delete("/todos/" + todo!.id.uuidString)
.count on(.okay)
.check()
}
}
That is how one can create an entire unit check situation for a REST API endpoint utilizing the Spec library. In fact there are a dozen different points that we might repair, reminiscent of higher enter object validation, unit check for the patch endpoint, higher checks for edge instances. Effectively, subsequent time. 😅
Through the use of Spec you may construct your expectations by describing the use case, then you may place your expectations on the described “specification” run the connected validators. The great factor about this declarative strategy is the clear self-explaining format that you may perceive with out taking an excessive amount of time on investigating the underlying Swift / Vapor code.
I consider that Spec is a enjoyable litte instrument that lets you write higher checks to your Swift backend apps. It has a really light-weight footprint, and the API is easy and straightforward to make use of. 💪
