Ensure endpoint path starts with a "/" (hummingbird-project#164)

* Ensure endpoint path starts with a "/"

* comment

Sources/Hummingbird/Router/RouterBuilder.swift

@@ -60,6 +60,8 @@ public final class HBRouterBuilder: HBRouterMethods {
     ///   - method: http method
     ///   - responder: handler to call
     public func add(_ path: String, method: HTTPMethod, responder: HBResponder) {
+        // ensure path starts with a "/"
+        let path = path.starts(with: "/") ? path : "/\(path)"
         self.trie.addEntry(.init(path), value: HBEndpointResponders(path: path)) { node in
             node.value!.addResponder(for: method, responder: middlewares.constructResponder(finalResponder: responder))
         }

Tests/HummingbirdTests/RouterTests.swift

@@ -55,6 +55,38 @@ final class RouterTests: XCTestCase {
         }
     }
 
+    /// Test endpointPath is prefixed with a "/"
+    func testEndpointPathPrefix() throws {
+        struct TestEndpointMiddleware: HBMiddleware {
+            func apply(to request: HBRequest, next: HBResponder) -> EventLoopFuture<HBResponse> {
+                guard let endpointPath = request.endpointPath else { return next.respond(to: request) }
+                return request.success(.init(status: .ok, body: .byteBuffer(ByteBuffer(string: endpointPath))))
+            }
+        }
+
+        let app = HBApplication(testing: .embedded)
+        app.middleware.add(TestEndpointMiddleware())
+        app.router.get("test") {
+            $0.endpointPath
+        }
+        app.router.post("/test2") {
+            $0.endpointPath
+        }
+
+        try app.XCTStart()
+        defer { app.XCTStop() }
+
+        try app.XCTExecute(uri: "/test/", method: .GET) { response in
+            let body = try XCTUnwrap(response.body)
+            XCTAssertEqual(String(buffer: body), "/test")
+        }
+
+        try app.XCTExecute(uri: "/test2/", method: .POST) { response in
+            let body = try XCTUnwrap(response.body)
+            XCTAssertEqual(String(buffer: body), "/test2")
+        }
+    }
+
     /// Test correct endpoints are called from group
     func testMethodEndpoint() throws {
         let app = HBApplication(testing: .embedded)