Add ExpressibleByStringInterpolation conformance to RouterPath

Sources/Hummingbird/Router/RouterPath.swift

@@ -13,7 +13,7 @@
 //===----------------------------------------------------------------------===//
 
 /// Split router path into components
-public struct RouterPath: Sendable, ExpressibleByStringLiteral, CustomStringConvertible {
+public struct RouterPath: Sendable, ExpressibleByStringLiteral, ExpressibleByStringInterpolation, CustomStringConvertible {
     public struct Element: Equatable, Sendable, CustomStringConvertible {
         package enum _Internal: Equatable, Sendable {
             case path(Substring)
@@ -175,7 +175,7 @@ public struct RouterPath: Sendable, ExpressibleByStringLiteral, CustomStringConv
     /// A textual representation of the RouterPath
     public let description: String
 
-    internal init(components: [Element]) {
+    init(components: [Element]) {
         self.components = components
         self.description = "/\(self.components.map(\.description).joined(separator: "/"))"
     }

Tests/HummingbirdTests/RouterTests.swift

@@ -618,6 +618,21 @@ final class RouterTests: XCTestCase {
             }
         }
     }
+
+    func testRouterPathStringInterpolation() async throws {
+        let route = "/test"
+        let router = Router()
+        router.get("\(route)") { _, _ in
+            return "TestString"
+        }
+        let app = Application(responder: router.buildResponder())
+        try await app.test(.router) { client in
+            try await client.execute(uri: "/test", method: .get) { response in
+                XCTAssertEqual(response.status, .ok)
+                XCTAssertEqual(response.headers[.contentLength], "10")
+            }
+        }
+    }
 }
 
 struct TestRouterContext2: RequestContext {