Add simple tests

jvm/src/test/scala/cs214/webapp/ServerSuite.scala

+package cs214.webapp
+package server
+package web
+
+import scala.util.Try
+
+import ujson.Value
+import io.undertow.Undertow
+import sttp.client4.quick.*
+import sttp.model.Uri
+
+import cs214.webapp.server.StateMachine
+import cs214.webapp.server.web.WebServer
+
+import scala.language.implicitConversions
+given unsafeURI: Conversion[String, Uri] with
+  def apply(uri: String): Uri = Uri.unsafeParse(uri)
+
+case class WebServerInfo(uri: String):
+  override def toString = uri
+
+class ServerSuite extends munit.FunSuite:
+  type Ping = String
+  type Pong = String
+  type State = String
+
+  object PingPong extends StateMachine[Ping, State, Pong]:
+    override def appInfo: AppInfo = AppInfo(
+      id = "stress", name = "Stress test", description = "", year = 2024
+    )
+
+    override object wire extends AppWire[Ping, Pong]:
+      override val eventFormat = StringWire
+      override val viewFormat = StringWire
+
+    override def init(clients: Seq[UserId]): String = ""
+    override def project(state: String)(userId: UserId): Pong = state
+    override def transition(state: String)(userId: UserId, event: Ping): Try[Seq[Action[State]]] = Try:
+      Seq(Action.Render(state))
+
+  WebServer.register(PingPong)
+
+  def withServer[T](body: WebServerInfo ?=> T): T =
+    object caskServer extends cask.Main:
+      def allRoutes = Seq(WebServerRoutes())
+
+    val (address, port) = ("localhost", 8091)
+    val server = Undertow.builder
+      .addHttpListener(port, address)
+      .setHandler(caskServer.defaultHandler)
+      .build
+    server.start()
+    val t =
+      try body(using WebServerInfo(f"http://${address}:${port}"))
+      finally server.stop()
+    t
+
+  def time[T](t: => T) =
+    val start = System.nanoTime
+    val result = t
+    val end = System.nanoTime
+    println(f"Elapsed: ${(end - start) / 1000000} ms")
+    result
+
+  import sttp.client4.quick.*
+
+  test("The main and app-selection pages respond to requests"):
+    withServer: ws ?=>
+      assert(quickRequest.get(ws.uri).send().code.isSuccess)
+      assert(quickRequest.get(f"$ws/app/${PingPong.appInfo.id}").send().code.isSuccess)
+
+  def createInstance(using ws: WebServerInfo) =
+    val users = Seq("yak", "hut", "kik")
+    val js = CreateInstanceRequest.Wire.encode:
+      CreateInstanceRequest(PingPong.appInfo.id, users)
+    val jsResponse = quickRequest
+      .post(f"$ws${Endpoints.Api.createInstance}")
+      .header("Content-Type", "application/json")
+      .body(ujson.write(js))
+      .send()
+      .body
+    CreateInstanceResponse.Wire.decode(ujson.read(jsResponse)).get
+
+  def instanceInfo(instanceId: String)(using ws: WebServerInfo) =
+    val resp = InstanceInfoResponse.Wire.decode:
+      ujson.read:
+        quickRequest.get(f"$ws${Endpoints.Api.instanceInfo}?instanceId=$instanceId").send().body
+    resp.get
+
+  test("Multiple instances can be created at the same time"):
+    withServer:
+      time:
+        for _ <- 1 to 10 do
+          val inst = createInstance
+          instanceInfo(inst.instanceId)