Fix kotlin-mcp-server sample (#459)

samples/kotlin-mcp-server/src/main/kotlin/io/modelcontextprotocol/sample/server/server.kt

@@ -31,6 +31,7 @@ import io.modelcontextprotocol.kotlin.sdk.types.ServerCapabilities
 import io.modelcontextprotocol.kotlin.sdk.types.TextContent
 import io.modelcontextprotocol.kotlin.sdk.types.TextResourceContents
 import kotlinx.coroutines.Job
+import kotlinx.coroutines.awaitCancellation
 import kotlinx.coroutines.runBlocking
 import kotlinx.io.asSink
 import kotlinx.io.asSource
@@ -102,13 +103,13 @@ fun configureServer(): Server {
     return server
 }
 
-fun runSseMcpServerWithPlainConfiguration(port: Int, wait: Boolean = true) {
+fun runSseMcpServerWithPlainConfiguration(port: Int, wait: Boolean = true): EmbeddedServer<*, *> {
     printBanner(port = port, path = "/sse")
     val serverSessions = ConcurrentMap<String, ServerSession>()
 
     val server = configureServer()
 
-    embeddedServer(CIO, host = "127.0.0.1", port = port) {
+    val ktorServer = embeddedServer(CIO, host = "127.0.0.1", port = port) {
         installCors()
         install(SSE)
         routing {
@@ -121,6 +122,7 @@ fun runSseMcpServerWithPlainConfiguration(port: Int, wait: Boolean = true) {
                     println("Server session closed for: ${transport.sessionId}")
                     serverSessions.remove(transport.sessionId)
                 }
+                awaitCancellation()
             }
             post("/message") {
                 val sessionId: String? = call.request.queryParameters["sessionId"]
@@ -139,6 +141,8 @@ fun runSseMcpServerWithPlainConfiguration(port: Int, wait: Boolean = true) {
             }
         }
     }.start(wait = wait)
+
+    return ktorServer
 }
 
 /**

samples/kotlin-mcp-server/src/test/kotlin/McpServerType.kt

@@ -0,0 +1,17 @@
+import io.ktor.server.engine.EmbeddedServer
+import io.modelcontextprotocol.sample.server.runSseMcpServerUsingKtorPlugin
+import io.modelcontextprotocol.sample.server.runSseMcpServerWithPlainConfiguration
+
+enum class McpServerType(
+    val sseEndpoint: String,
+    val serverFactory: (port: Int) -> EmbeddedServer<*, *>
+) {
+    KTOR_PLUGIN(
+        sseEndpoint = "",
+        serverFactory = { port -> runSseMcpServerUsingKtorPlugin(port, wait = false) }
+    ),
+    PLAIN_CONFIGURATION(
+        sseEndpoint = "/sse",
+        serverFactory = { port -> runSseMcpServerWithPlainConfiguration(port, wait = false) }
+    )
+}

samples/kotlin-mcp-server/src/test/kotlin/SseServerIntegrationTest.kt

@@ -11,9 +11,9 @@ import kotlin.test.assertNotNull
 import kotlin.test.assertNull
 import kotlin.test.assertTrue
 
-class SseServerIntegrationTest {
+abstract class SseServerIntegrationTestBase {
 
-    private val client: Client = TestEnvironment.client
+    abstract val client: Client
 
     @Test
     fun `should list tools`(): Unit = runBlocking {
@@ -88,3 +88,13 @@ class SseServerIntegrationTest {
         assertEquals(expected = "text", actual = "${content.type}".lowercase())
     }
 }
+
+class SseServerKtorPluginIntegrationTest : SseServerIntegrationTestBase() {
+    private val testEnvironment = TestEnvironment(McpServerType.KTOR_PLUGIN)
+    override val client: Client = testEnvironment.client
+}
+
+class SseServerPlainConfigurationIntegrationTest : SseServerIntegrationTestBase() {
+    private val testEnvironment = TestEnvironment(McpServerType.PLAIN_CONFIGURATION)
+    override val client: Client = testEnvironment.client
+}

samples/kotlin-mcp-server/src/test/kotlin/TestEnvironment.kt

@@ -1,34 +1,34 @@
 import io.ktor.client.HttpClient
 import io.ktor.client.engine.cio.CIO
 import io.ktor.client.plugins.sse.SSE
-import io.modelcontextprotocol.kotlin.sdk.Implementation
+import io.ktor.server.engine.EmbeddedServer
 import io.modelcontextprotocol.kotlin.sdk.client.Client
 import io.modelcontextprotocol.kotlin.sdk.client.mcpSseTransport
-import io.modelcontextprotocol.sample.server.runSseMcpServerUsingKtorPlugin
+import io.modelcontextprotocol.kotlin.sdk.types.Implementation
 import kotlinx.coroutines.runBlocking
 import java.util.concurrent.TimeUnit
 
-object TestEnvironment {
+class TestEnvironment(private val serverConfig: McpServerType) {
 
-    val server = runSseMcpServerUsingKtorPlugin(0, wait = false)
+    val server: EmbeddedServer<*, *> = serverConfig.serverFactory(0)
     val client: Client
 
     init {
         client = runBlocking {
             val port = server.engine.resolvedConnectors().single().port
-            initClient(port)
+            initClient(port, serverConfig)
         }
 
         Runtime.getRuntime().addShutdownHook(
             Thread {
-                println("🏁 Shutting down server")
+                println("🏁 Shutting down server (${serverConfig.name})")
                 server.stop(500, 700, TimeUnit.MILLISECONDS)
                 println("☑️ Shutdown complete")
             },
         )
     }
 
-    private suspend fun initClient(port: Int): Client {
+    private suspend fun initClient(port: Int, config: McpServerType): Client {
         val client = Client(
             Implementation(name = "test-client", version = "0.1.0"),
         )
@@ -37,13 +37,7 @@ object TestEnvironment {
             install(SSE)
         }
 
-        // Create a transport wrapper that captures the session ID and received messages
-        val transport = httpClient.mcpSseTransport {
-            url {
-                this.host = "127.0.0.1"
-                this.port = port
-            }
-        }
+        val transport = httpClient.mcpSseTransport("http://127.0.0.1:$port/${config.sseEndpoint}")
         client.connect(transport)
         return client
     }