Refactor TypeScript integration tests

- Use dynamic random ports for server setup
- Add `Awaitility` for reliable server readiness checks and improved concurrency handling
- Update test server start logic to return resolved port
- Replace `StringBuilder` with `StringBuffer`
- Remove redundant port discovery and wait logic

Author: kpavlov

kotlin-sdk-test/src/jvmTest/kotlin/io/modelcontextprotocol/kotlin/sdk/integration/kotlin/KotlinTestBase.kt

@@ -12,12 +12,12 @@ import io.modelcontextprotocol.kotlin.sdk.ServerCapabilities
 import io.modelcontextprotocol.kotlin.sdk.client.Client
 import io.modelcontextprotocol.kotlin.sdk.client.SseClientTransport
 import io.modelcontextprotocol.kotlin.sdk.integration.utils.Retry
+import io.modelcontextprotocol.kotlin.sdk.integration.utils.port
 import io.modelcontextprotocol.kotlin.sdk.server.Server
 import io.modelcontextprotocol.kotlin.sdk.server.ServerOptions
 import io.modelcontextprotocol.kotlin.sdk.server.mcp
 import kotlinx.coroutines.runBlocking
 import kotlinx.coroutines.withTimeout
-import org.awaitility.kotlin.await
 import org.junit.jupiter.api.AfterEach
 import org.junit.jupiter.api.BeforeEach
 import kotlin.time.Duration.Companion.seconds
@@ -40,12 +40,7 @@ abstract class KotlinTestBase {
     @BeforeEach
     fun setUp() {
         setupServer()
-        await
-            .ignoreExceptions()
-            .until {
-                port = runBlocking { serverEngine.engine.resolvedConnectors().first().port }
-                port != 0
-            }
+        port = serverEngine.port()
         runBlocking {
             setupClient()
         }
@@ -74,7 +69,7 @@ abstract class KotlinTestBase {
 
         configureServer()
 
-        serverEngine = embeddedServer(ServerCIO, host = host, port = port) {
+        serverEngine = embeddedServer(ServerCIO, host = host, port = 0) {
             install(ServerSSE)
             routing {
                 mcp { server }

kotlin-sdk-test/src/jvmTest/kotlin/io/modelcontextprotocol/kotlin/sdk/integration/typescript/KotlinServerForTypeScriptClient.kt

@@ -37,6 +37,7 @@ import io.modelcontextprotocol.kotlin.sdk.ServerCapabilities
 import io.modelcontextprotocol.kotlin.sdk.TextContent
 import io.modelcontextprotocol.kotlin.sdk.TextResourceContents
 import io.modelcontextprotocol.kotlin.sdk.Tool
+import io.modelcontextprotocol.kotlin.sdk.integration.utils.port
 import io.modelcontextprotocol.kotlin.sdk.server.Server
 import io.modelcontextprotocol.kotlin.sdk.server.ServerOptions
 import io.modelcontextprotocol.kotlin.sdk.shared.AbstractTransport
@@ -65,10 +66,10 @@ class KotlinServerForTypeScriptClient {
     private val jsonFormat = Json { ignoreUnknownKeys = true }
     private var server: EmbeddedServer<*, *>? = null
 
-    fun start(port: Int = 3000) {
-        logger.info { "Starting HTTP server on port $port" }
+    fun start(): Int {
+        logger.info { "Starting HTTP server on random port" }
 
-        server = embeddedServer(CIO, port = port) {
+        server = embeddedServer(CIO, port = 0) {
             routing {
                 get("/mcp") {
                     val sessionId = call.request.header("mcp-session-id")
@@ -186,7 +187,9 @@ class KotlinServerForTypeScriptClient {
             }
         }
 
-        server?.start(wait = false)
+        val theServer = requireNotNull(server) { "Server must be created" }
+        theServer.start(wait = false)
+        return theServer.port()
     }
 
     fun stop() {
@@ -357,6 +360,8 @@ class HttpServerTransport(private val sessionId: String) : AbstractTransport() {
                     write("\n\n")
                     flush()
                 }
+            } catch (e: CancellationException) {
+                logger.info(e) { e.message }
             } catch (e: Exception) {
                 logger.warn(e) { "SSE stream terminated for session: $sessionId" }
             } finally {

kotlin-sdk-test/src/jvmTest/kotlin/io/modelcontextprotocol/kotlin/sdk/integration/typescript/TypeScriptClientKotlinServerTest.kt

@@ -1,29 +1,26 @@
 package io.modelcontextprotocol.kotlin.sdk.integration.typescript
 
 import kotlinx.coroutines.test.runTest
+import org.awaitility.kotlin.await
 import org.junit.jupiter.api.AfterEach
 import org.junit.jupiter.api.BeforeEach
 import org.junit.jupiter.api.Test
 import org.junit.jupiter.api.Timeout
 import java.util.concurrent.TimeUnit
 import kotlin.test.assertTrue
+import kotlin.time.Duration.Companion.milliseconds
+import kotlin.time.toJavaDuration
 
 class TypeScriptClientKotlinServerTest : TypeScriptTestBase() {
 
-    private var port: Int = 0
     private lateinit var serverUrl: String
     private var httpServer: KotlinServerForTypeScriptClient? = null
 
     @BeforeEach
     fun setUp() {
-        port = findFreePort()
-        serverUrl = "http://localhost:$port/mcp"
-        killProcessOnPort(port)
         httpServer = KotlinServerForTypeScriptClient()
-        httpServer?.start(port)
-        if (!waitForPort(port = port)) {
-            throw IllegalStateException("Kotlin test server did not become ready on localhost:$port within timeout")
-        }
+        val port = httpServer!!.start()
+        serverUrl = "http://localhost:$port/mcp"
         println("Kotlin server started on port $port")
     }
 
@@ -143,10 +140,13 @@ class TypeScriptClientKotlinServerTest : TypeScriptTestBase() {
             }
             threads.add(thread)
             thread.start()
-            Thread.sleep(500)
         }
 
-        threads.forEach { it.join() }
+        await
+            .pollInterval(100.milliseconds.toJavaDuration())
+            .until {
+                outputs.size == clientCount
+            }
 
         if (exceptions.isNotEmpty()) {
             println(

kotlin-sdk-test/src/jvmTest/kotlin/io/modelcontextprotocol/kotlin/sdk/integration/typescript/TypeScriptEdgeCasesTest.kt

@@ -20,14 +20,9 @@ class TypeScriptEdgeCasesTest : TypeScriptTestBase() {
 
     @BeforeEach
     fun setUp() {
-        port = findFreePort()
-        serverUrl = "http://localhost:$port/mcp"
-        killProcessOnPort(port)
         httpServer = KotlinServerForTypeScriptClient()
-        httpServer?.start(port)
-        if (!waitForPort(port = port)) {
-            throw IllegalStateException("Kotlin test server did not become ready on localhost:$port within timeout")
-        }
+        port = httpServer!!.start()
+        serverUrl = "http://localhost:$port/mcp"
         println("Kotlin server started on port $port")
     }
 

kotlin-sdk-test/src/jvmTest/kotlin/io/modelcontextprotocol/kotlin/sdk/integration/typescript/TypeScriptTestBase.kt

@@ -109,7 +109,7 @@ abstract class TypeScriptTestBase {
                 .redirectErrorStream(true)
                 .start()
 
-            val output = StringBuilder()
+            val output = StringBuffer()
             BufferedReader(InputStreamReader(process.inputStream)).use { reader ->
                 var line: String?
                 while (reader.readLine().also { line = it } != null) {

kotlin-sdk-test/src/jvmTest/kotlin/io/modelcontextprotocol/kotlin/sdk/integration/utils/EmbeddedServerExtensions.kt

@@ -0,0 +1,17 @@
+package io.modelcontextprotocol.kotlin.sdk.integration.utils
+
+import io.ktor.server.engine.EmbeddedServer
+import kotlinx.coroutines.runBlocking
+import org.awaitility.kotlin.await
+
+internal fun EmbeddedServer<*, *>.port(): Int {
+    var port = 0
+    val server = this
+    await
+        .ignoreExceptions()
+        .until {
+            port = runBlocking { server.engine.resolvedConnectors().first().port }
+            port != 0
+        }
+    return port
+}