Web support for the Website service (#17)

This PR contains the work done to introduce a new Web Swift package that provides a reusable, declarative way to register route controllers on a Hummingbird router, then adopt it in the Website service.

To provide further details about the work:

* Web package
  * The `RouterController` protocol — a Sendable protocol to group controllers behind one `routes` property.
  * The `RouteCollectionBuilder`  — a result builder that collects controllers' route collections into a stack, with full support for optionals, conditionals, and arrays.
  * The `addController(_:)` method — a `RouterMethods` extension letting controllers be listed declaratively and adding each one's routes at the router root.

* Website service
  * Added Web as a dependency of the _WebsiteLibrary_ target.
  * Conformed the `RootController` and `HealthController`controllers to the `RouterController` protocol.
  * Updated the `App+Build` extension to to use the cleaner `router.addController { … }` instead.

Reviewed-on: rock-n-code/loud-amsterdam#17
Co-authored-by: Javier Cicchelli <javier@rock-n-code.com>
Co-committed-by: Javier Cicchelli <javier@rock-n-code.com>

Packages/Web/Tests/Cases/Public/Extensions/RouterMethods+RouteCollectionsTests.swift

@@ -0,0 +1,155 @@
+import Hummingbird
+import HummingbirdTesting
+import Testing
+
+@testable import Web
+
+@Suite("addController method")
+struct RouterMethodsTests {
+
+    // MARK: Functional tests
+
+    @Test
+    func `adds the routes of every listed controller`() async throws {
+        let router = Router()
+
+        router.addController {
+            StubController(path: "first")
+            StubController(path: "second")
+        }
+
+        try await Application(router: router).test(.router) { client in
+            try await client.execute(
+                uri: "/first",
+                method: .get
+            ) { response in
+                #expect(response.status == .ok)
+                #expect(String(buffer: response.body) == "first")
+            }
+
+            try await client.execute(
+                uri: "/second",
+                method: .get
+            ) { response in
+                #expect(response.status == .ok)
+                #expect(String(buffer: response.body) == "second")
+            }
+        }
+    }
+
+    @Test(arguments: [true, false])
+    func `adds a controller behind a condition only when the condition holds`(
+        condition: Bool
+    ) async throws {
+        let router = Router()
+
+        router.addController {
+            StubController(path: "always")
+
+            if condition {
+                StubController(path: "conditional")
+            }
+        }
+
+        try await Application(router: router).test(.router) { client in
+            try await client.execute(
+                uri: "/always",
+                method: .get
+            ) { response in
+                #expect(response.status == .ok)
+            }
+
+            try await client.execute(
+                uri: "/conditional",
+                method: .get
+            ) { response in
+                #expect(response.status == (condition ? .ok : .notFound))
+            }
+        }
+    }
+
+    @Test(arguments: [true, false])
+    func `adds only the taken branch of a condition`(
+        takesFirst: Bool
+    ) async throws {
+        let router = Router()
+
+        router.addController {
+            if takesFirst {
+                StubController(path: "first")
+            } else {
+                StubController(path: "second")
+            }
+        }
+
+        try await Application(router: router).test(.router) { client in
+            try await client.execute(
+                uri: "/first",
+                method: .get
+            ) { response in
+                #expect(response.status == (takesFirst ? .ok : .notFound))
+            }
+
+            try await client.execute(
+                uri: "/second",
+                method: .get
+            ) { response in
+                #expect(response.status == (takesFirst ? .notFound : .ok))
+            }
+        }
+    }
+
+    @Test
+    func `adds a controller for every iteration of a loop`() async throws {
+        let paths = ["one", "two", "three"]
+        let router = Router()
+
+        router.addController {
+            for path in paths {
+                StubController(path: path)
+            }
+        }
+
+        try await Application(router: router).test(.router) { client in
+            for path in paths {
+                try await client.execute(
+                    uri: "/\(path)",
+                    method: .get
+                ) { response in
+                    #expect(response.status == .ok)
+                    #expect(String(buffer: response.body) == path)
+                }
+            }
+        }
+    }
+
+    @Test
+    func `returns the router so calls can be chained`() async throws {
+        let router = Router()
+
+        router
+            .addController {
+                StubController(path: "first")
+            }
+            .addController {
+                StubController(path: "second")
+            }
+
+        try await Application(router: router).test(.router) { client in
+            try await client.execute(
+                uri: "/first",
+                method: .get
+            ) { response in
+                #expect(response.status == .ok)
+            }
+
+            try await client.execute(
+                uri: "/second",
+                method: .get
+            ) { response in
+                #expect(response.status == .ok)
+            }
+        }
+    }
+
+}

Packages/Web/Tests/Utils/Controllers/StubController.swift

@@ -0,0 +1,30 @@
+import Hummingbird
+import Web
+
+/// A controller serving its path back as plain text, used to observe route registration.
+struct StubController {
+
+    // MARK: Properties
+
+    /// The path the controller serves, also returned as the response body.
+    let path: String
+
+}
+
+// MARK: - RouterController
+
+extension StubController: RouterController {
+
+    // MARK: Properties
+
+    var routes: RouteCollection<BasicRequestContext> {
+        let routes = RouteCollection(context: BasicRequestContext.self)
+
+        routes.get(.init(path)) { _, _ in
+            self.path
+        }
+
+        return routes
+    }
+
+}