Add tests to server samples (#369)

Add test for sse server
TODO: Add tests for the other protocols

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## Motivation and Context
<!-- Why is this change needed? What problem does it solve? -->

## How Has This Been Tested?
<!-- Have you tested this in a real application? Which scenarios were
tested? -->

## Breaking Changes
<!-- Will users need to update their code or configurations? -->

## Types of changes
<!-- What types of changes does your code introduce? Put an `x` in all
the boxes that apply: -->
- [ ] Bug fix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to change)
- [ ] Documentation update
- [x] Tests

## Checklist
<!-- Go over all the following points, and put an `x` in all the boxes
that apply. -->
- [x] I have read the [MCP
Documentation](https://modelcontextprotocol.io)
- [x] My code follows the repository's style guidelines
- [x] New and existing tests pass locally
- [ ] I have added appropriate error handling
- [ ] I have added or updated documentation as needed

## Additional context
<!-- Add any other context, implementation notes, or design decisions
-->

samples/kotlin-mcp-server/build.gradle.kts

@@ -16,6 +16,10 @@ dependencies {
     implementation(libs.mcp.kotlin.server)
     implementation(libs.ktor.server.cio)
     implementation(libs.slf4j.simple)
+
+    testImplementation(libs.mcp.kotlin.client)
+    testImplementation(libs.ktor.client.cio)
+    testImplementation(kotlin("test"))
 }
 
 tasks.test {

samples/kotlin-mcp-server/gradle/libs.versions.toml

@@ -3,12 +3,13 @@ kotlin = "2.2.21"
 ktor = "3.2.3"
 mcp-kotlin = "0.7.4"
 slf4j = "2.0.17"
-serialization = "1.9.0"
 
 [libraries]
 ktor-bom = { group = "io.ktor", name = "ktor-bom", version.ref = "ktor" }
 ktor-server-cio = { group = "io.ktor", name = "ktor-server-cio" }
+ktor-client-cio = { group = "io.ktor", name = "ktor-client-cio" }
 mcp-kotlin-server = { group = "io.modelcontextprotocol", name = "kotlin-sdk-server", version.ref = "mcp-kotlin" }
+mcp-kotlin-client = { group = "io.modelcontextprotocol", name = "kotlin-sdk-client", version.ref = "mcp-kotlin" }
 slf4j-simple = { group = "org.slf4j", name = "slf4j-simple", version.ref = "slf4j" }
 
 [plugins]

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

@@ -100,7 +100,7 @@ fun configureServer(): Server {
     return server
 }
 
-fun runSseMcpServerWithPlainConfiguration(port: Int) {
+fun runSseMcpServerWithPlainConfiguration(port: Int, wait: Boolean = true) {
     val serverSessions = ConcurrentMap<String, ServerSession>()
     println("Starting SSE server on port $port")
     println("Use inspector to connect to http://localhost:$port/sse")
@@ -136,7 +136,7 @@ fun runSseMcpServerWithPlainConfiguration(port: Int) {
                 transport.handlePostMessage(call)
             }
         }
-    }.start(wait = true)
+    }.start(wait = wait)
 }
 
 /**
@@ -147,7 +147,7 @@ fun runSseMcpServerWithPlainConfiguration(port: Int) {
  *
  * @param port The port number on which the SSE MCP server will listen for client connections.
  */
-fun runSseMcpServerUsingKtorPlugin(port: Int) {
+fun runSseMcpServerUsingKtorPlugin(port: Int, wait: Boolean = true) {
     println("Starting SSE server on port $port")
     println("Use inspector to connect to http://localhost:$port/sse")
 
@@ -155,7 +155,7 @@ fun runSseMcpServerUsingKtorPlugin(port: Int) {
         mcp {
             return@mcp configureServer()
         }
-    }.start(wait = true)
+    }.start(wait = wait)
 }
 
 /**

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

@@ -0,0 +1,83 @@
+import io.ktor.client.HttpClient
+import io.ktor.client.engine.cio.CIO
+import io.ktor.client.plugins.sse.SSE
+import io.modelcontextprotocol.kotlin.sdk.EmptyJsonObject
+import io.modelcontextprotocol.kotlin.sdk.Implementation
+import io.modelcontextprotocol.kotlin.sdk.TextContent
+import io.modelcontextprotocol.kotlin.sdk.client.Client
+import io.modelcontextprotocol.kotlin.sdk.client.mcpSseTransport
+import io.modelcontextprotocol.sample.server.runSseMcpServerUsingKtorPlugin
+import kotlinx.coroutines.runBlocking
+import org.junit.jupiter.api.BeforeAll
+import org.junit.jupiter.api.TestInstance
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertIs
+
+@TestInstance(TestInstance.Lifecycle.PER_CLASS)
+class SseServerIntegrationTest {
+
+    companion object {
+        private const val PORT = 3002
+    }
+
+    private lateinit var client: Client
+
+    private fun initClient(port: Int) {
+        client = Client(
+            Implementation(name = "test-client", version = "0.1.0"),
+        )
+
+        val httpClient = HttpClient(CIO) {
+            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
+            }
+        }
+        runBlocking {
+            client.connect(transport)
+        }
+    }
+
+    @BeforeAll
+    fun setUp() {
+        runSseMcpServerUsingKtorPlugin(PORT, wait = false)
+        initClient(PORT)
+    }
+
+    @Test
+    fun `should get tools`(): Unit = runBlocking {
+        val tools = client.listTools().tools
+
+        assertEquals(expected = listOf("kotlin-sdk-tool"), actual = tools.map { it.name })
+    }
+
+    @Test
+    fun `should get prompts`(): Unit = runBlocking {
+        val prompts = client.listPrompts().prompts
+
+        assertEquals(expected = listOf("Kotlin Developer"), actual = prompts.map { it.name })
+    }
+
+    @Test
+    fun `should get resources`(): Unit = runBlocking {
+        val resources = client.listResources().resources
+
+        assertEquals(expected = listOf("Web Search"), actual = resources.map { it.name })
+    }
+
+    @Test
+    fun `should call tool`(): Unit = runBlocking {
+        val toolResult = client.callTool("kotlin-sdk-tool", EmptyJsonObject)
+        val content = toolResult?.content?.single()
+        assertIs<TextContent>(content, "Tool result should be a text content")
+
+        assertEquals(expected = "Hello, world!", actual = content.text)
+        assertEquals(expected = "text", actual = content.type)
+    }
+}