Writing exams utilizing XCTVapor
In my earlier article I confirmed you the right way to construct a sort protected RESTful API utilizing Vapor. This time we’ll prolong that challenge a bit and write some exams utilizing the Vapor testing device to find the underlying points within the API layer. First we’ll use XCTVapor library, then we migrate to a light-weight declarative testing framework (Spec) constructed on high of that.
Earlier than we begin testing our software, now we have to guarantee that if the app runs in testing mode we register an inMemory database as a substitute of our native SQLite file. We are able to merely alter the configuration and test the setting and set the db driver primarily based on it.
import Vapor
import Fluent
import FluentSQLiteDriver
public func configure(_ app: Software) throws {
if app.setting == .testing {
app.databases.use(.sqlite(.reminiscence), as: .sqlite, isDefault: true)
}
else {
app.databases.use(.sqlite(.file("Assets/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 concerning the fundamentals of testing Vapor endpoints. Sadly it will not let you know a lot about testing web sites or complicated API calls. ✅
We will make a easy check that checks the return sort for our Todo record endpoint.
@testable import App
import TodoApi
import Fluent
import XCTVapor
remaining class AppTests: XCTestCase {
func testTodoList() throws {
let app = Software(.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)
})
}
}As you’ll be able to see first we setup & configure our software, then we ship a GET request to the /todos/ endpoint. After now we have a response we will test the standing code, the content material sort and we will attempt to decode the response physique as a sound paginated todo record merchandise object.
This check case was fairly easy, now let’s write a brand new unit check for the todo merchandise creation.
@testable import App
import TodoApi
import Fluent
import XCTVapor
remaining class AppTests: XCTestCase {
func testCreateTodo() throws {
let app = Software(.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 would wish to submit a brand new TodoCreateObject as a POST information, luckily XCTVapor may also help us with the beforeRequest block. We are able to merely encode the enter object as a content material, then within the response handler we will test the HTTP standing code (it must be created) decode the anticipated response object (TodoGetObject) and validate the sphere values.
I additionally up to date the TodoCreateObject, because it doesn’t make an excessive amount of sense to have an non-obligatory Bool subject and we will 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 a substitute of a .created worth. We are able to simply repair this within the create methodology 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 = Software(.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)
})
}Properly, that is unhealthy, we should not be capable to create a todo merchandise with out a title. We may use the built-in validation API to test consumer enter, however truthfully talking that is not the very best strategy.
My problem with validation is that initially you’ll be able to’t return customized error messages and the opposite principal motive is that validation in Vapor shouldn’t be async by default. Finally you may face a state of affairs when you’ll want to validate an object primarily based on a db name, then you’ll be able to’t match that a part of the thing validation course of into different non-async subject validation. IMHO, this must be unified. 🥲
Fort the sake of simplicity we’ll begin with a customized validation methodology, this time with none async logic concerned, in a while I am going to present you the right way 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, motive: "Title is required")
}
}
}Within the create controller we will merely name the throwing validateCreate operate, if one thing goes mistaken the Abort error can be returned as a response. It is usually doable to make use of an async methodology (return with an EventLoopFuture) then await (flatMap) the decision and return our newly created todo if every thing was advantageous.
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 now we have to do is to replace our check case and test for an error response.
struct ErrorResponse: Content material {
let error: Bool
let motive: String
}
func testCreateInvalidTodo() throws {
let app = Software(.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.motive, "Title is required")
})
}Writing exams is a good way to debug our server facet Swift code and double test our API endpoints. My solely problem with this strategy is that the code is not an excessive amount of self-explaining.
Declarative unit exams utilizing Spec XCTVapor and the complete check framework works simply nice, however I had a small downside with it. In case you ever labored with JavaScript or TypeScript you may need heard concerning the SuperTest library. This little npm bundle provides us a declarative syntactical sugar for testing HTTP requests, which I favored manner an excessive amount of to return to common XCTVapor-based check circumstances.
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 observe, utilizing a real-world instance. 🙃
import PackageDescription
let bundle = Bundle(
identify: "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(identify: "Run", dependencies: [.target(name: "App")]),
.testTarget(identify: "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? Properly, we will create a brand new merchandise, then replace it and test if the outcomes are legitimate.
import Spec
func testUpdateTodo() throws {
let app = Software(.testing)
defer { app.shutdown() }
attempt configure(app)
var existingTodo: TodoGetObject?
attempt app
.describe("A sound 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 completed"
attempt app
.describe("Todo must 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 had been capable of create a todo object, it’s the very same create expectation as we used to put in writing with the assistance of the XCTVapor framework.
IMHO the general code high quality is manner 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 should be extra easy to know check circumstances. In case you evaluate the 2 variations the create case the second is trivial to know, however within the first one you really should take a deeper take a look at every line to know what is going on on.
Okay, yet another check earlier than we cease, let me present you the right way to describe the delete endpoint. We will 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 motive: String
}
@discardableResult
non-public func createTodo(app: Software, enter: TodoCreateObject) throws -> TodoGetObject {
var existingTodo: TodoGetObject?
attempt app
.describe("A sound 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 = Software(.testing)
defer { app.shutdown() }
attempt configure(app)
attempt app
.describe("A sound todo record web page must be returned.")
.get("/todos/")
.count on(.okay)
.count on(.json)
.count on(Web page<TodoListObject>.self)
.check()
}
func testCreateTodo() throws {
let app = Software(.testing)
defer { app.shutdown() }
attempt configure(app)
attempt createTodo(app: app, enter: TodoCreateObject(title: "Write a todo tutorial"))
}
func testCreateInvalidTodo() throws {
let app = Software(.testing)
defer { app.shutdown() }
attempt configure(app)
attempt app
.describe("An invalid title response must be returned")
.publish("/todos/")
.physique(TodoCreateObject(title: ""))
.count on(.badRequest)
.count on(.json)
.count on(ErrorResponse.self) { error in
XCTAssertEqual(error.motive, "Title is required")
}
.check()
}
func testUpdateTodo() throws {
let app = Software(.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 completed"
attempt app
.describe("Todo must 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 = Software(.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 must 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 may repair, reminiscent of higher enter object validation, unit check for the patch endpoint, higher exams for edge circumstances. Properly, subsequent time. 😅
By utilizing Spec you’ll be able to construct your expectations by describing the use case, then you’ll be able to place your expectations on the described “specification” run the hooked up validators. The great factor about this declarative strategy is the clear self-explaining format which you can perceive with out taking an excessive amount of time on investigating the underlying Swift / Vapor code.
I imagine that Spec is a enjoyable little device that lets you write higher exams to your Swift backend apps. It has a really light-weight footprint, and the API is easy and simple to make use of. 💪