Use single Tomcat instance per test class

- Instead of running one Tomcat per test method, run one per test
- Improves the testing time of Servlet-based tests

Signed-off-by: Daniel Garnier-Moiroux <git@garnier.wf>

mcp-test/src/test/java/io/modelcontextprotocol/server/HttpServletSseIntegrationTests.java

@@ -27,7 +27,9 @@ import jakarta.servlet.http.HttpServletResponse;
 import org.apache.catalina.LifecycleException;
 import org.apache.catalina.LifecycleState;
 import org.apache.catalina.startup.Tomcat;
+import org.junit.jupiter.api.AfterAll;
 import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.Timeout;
@@ -44,14 +46,42 @@ class HttpServletSseIntegrationTests extends AbstractMcpClientServerIntegrationT
 
 	private static final String CUSTOM_MESSAGE_ENDPOINT = "/otherPath/mcp/message";
 
-	private HttpServletSseServerTransportProvider mcpServerTransportProvider;
+	// Tomcat is started once for the whole class; each test swaps in its own transport
+	private static final TomcatTestUtil.DelegatingServlet MCP_SERVLET = new TomcatTestUtil.DelegatingServlet();
 
-	private Tomcat tomcat;
+	private static Tomcat tomcat;
+
+	private HttpServletSseServerTransportProvider mcpServerTransportProvider;
 
 	static Stream<Arguments> clientsForTesting() {
 		return Stream.of(Arguments.of("httpclient"));
 	}
 
+	@BeforeAll
+	public static void beforeAll() {
+		tomcat = TomcatTestUtil.createTomcatServer("", PORT, MCP_SERVLET);
+		try {
+			tomcat.start();
+			assertThat(tomcat.getServer().getState()).isEqualTo(LifecycleState.STARTED);
+		}
+		catch (Exception e) {
+			throw new RuntimeException("Failed to start Tomcat", e);
+		}
+	}
+
+	@AfterAll
+	public static void afterAll() {
+		if (tomcat != null) {
+			try {
+				tomcat.stop();
+				tomcat.destroy();
+			}
+			catch (LifecycleException e) {
+				throw new RuntimeException("Failed to stop Tomcat", e);
+			}
+		}
+	}
+
 	@BeforeEach
 	public void before() {
 		// Create and configure the transport provider
@@ -61,15 +91,7 @@ class HttpServletSseIntegrationTests extends AbstractMcpClientServerIntegrationT
 			.sseEndpoint(CUSTOM_SSE_ENDPOINT)
 			.maxRequestSize(MAX_REQUEST_SIZE)
 			.build();
-
+		MCP_SERVLET.setDelegate(mcpServerTransportProvider);
-		tomcat = TomcatTestUtil.createTomcatServer("", PORT, mcpServerTransportProvider);
-		try {
-			tomcat.start();
-			assertThat(tomcat.getServer().getState()).isEqualTo(LifecycleState.STARTED);
-		}
-		catch (Exception e) {
-			throw new RuntimeException("Failed to start Tomcat", e);
-		}
 
 		clientBuilders
 			.put("httpclient",
@@ -93,15 +115,6 @@ class HttpServletSseIntegrationTests extends AbstractMcpClientServerIntegrationT
 		if (mcpServerTransportProvider != null) {
 			mcpServerTransportProvider.closeGracefully().block();
 		}
-		if (tomcat != null) {
-			try {
-				tomcat.stop();
-				tomcat.destroy();
-			}
-			catch (LifecycleException e) {
-				throw new RuntimeException("Failed to stop Tomcat", e);
-			}
-		}
 	}
 
 	@Override

mcp-test/src/test/java/io/modelcontextprotocol/server/HttpServletStatelessIntegrationTests.java

@@ -16,12 +16,7 @@ import java.util.Map;
 import java.util.concurrent.atomic.AtomicReference;
 import java.util.function.BiFunction;
 import java.util.function.Function;
-import java.util.function.Function;
 
-import ch.qos.logback.classic.Level;
-import ch.qos.logback.classic.Logger;
-import ch.qos.logback.classic.spi.ILoggingEvent;
-import ch.qos.logback.core.read.ListAppender;
 import ch.qos.logback.classic.Level;
 import ch.qos.logback.classic.Logger;
 import ch.qos.logback.classic.spi.ILoggingEvent;
@@ -54,21 +49,17 @@ import net.javacrumbs.jsonunit.core.Option;
 import org.apache.catalina.LifecycleException;
 import org.apache.catalina.LifecycleState;
 import org.apache.catalina.startup.Tomcat;
-import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.AfterAll;
-import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.Timeout;
 import org.slf4j.LoggerFactory;
 import reactor.core.publisher.Mono;
 import reactor.test.StepVerifier;
-import org.slf4j.LoggerFactory;
-import reactor.core.publisher.Mono;
-import reactor.test.StepVerifier;
 
 import org.springframework.mock.web.MockHttpServletRequest;
 import org.springframework.mock.web.MockHttpServletResponse;
 import org.springframework.web.client.RestClient;
-
 import static io.modelcontextprotocol.server.transport.HttpServletStatelessServerTransport.APPLICATION_JSON;
 import static io.modelcontextprotocol.server.transport.HttpServletStatelessServerTransport.TEXT_EVENT_STREAM;
 import static io.modelcontextprotocol.util.McpJsonMapperUtils.JSON_MAPPER;
@@ -89,7 +80,9 @@ class HttpServletStatelessIntegrationTests {
 
 	private static final int MAX_REQUEST_SIZE = 2048;
 
-	private HttpServletStatelessServerTransport mcpStatelessServerTransport;
+	private static Tomcat tomcat;
+
+	private static HttpServletStatelessServerTransport mcpStatelessServerTransport;
 
 	private final McpClient.SyncSpec clientBuilder = McpClient
 		.sync(HttpClientStreamableHttpTransport.builder("http://localhost:" + PORT)
@@ -98,11 +91,9 @@ class HttpServletStatelessIntegrationTests {
 		.initializationTimeout(Duration.ofHours(10))
 		.requestTimeout(Duration.ofHours(10));
 
-	private Tomcat tomcat;
+	@BeforeAll
-
+	public static void beforeAll() {
-	@BeforeEach
+		mcpStatelessServerTransport = HttpServletStatelessServerTransport.builder()
-	public void before() {
-		this.mcpStatelessServerTransport = HttpServletStatelessServerTransport.builder()
 			.messageEndpoint(CUSTOM_MESSAGE_ENDPOINT)
 			.maxRequestSize(MAX_REQUEST_SIZE)
 			.build();
@@ -117,8 +108,8 @@ class HttpServletStatelessIntegrationTests {
 		}
 	}
 
-	@AfterEach
+	@AfterAll
-	public void after() {
+	public static void afterAll() {
 		if (mcpStatelessServerTransport != null) {
 			mcpStatelessServerTransport.closeGracefully().block();
 		}
@@ -155,7 +146,7 @@ class HttpServletStatelessIntegrationTests {
 					return callResponse;
 				});
 
-		var mcpServer = McpServer.sync(mcpStatelessServerTransport)
+		McpServer.sync(mcpStatelessServerTransport)
 			.capabilities(ServerCapabilities.builder().tools(true).build())
 			.tools(tool1)
 			.build();
@@ -173,22 +164,16 @@ class HttpServletStatelessIntegrationTests {
 			assertThat(response).isNotNull();
 			assertThat(response).isEqualTo(callResponse);
 		}
-		finally {
-			mcpServer.close();
-		}
 	}
 
 	@Test
 	void testInitialize() {
-		var mcpServer = McpServer.sync(mcpStatelessServerTransport).build();
+		McpServer.sync(mcpStatelessServerTransport).build();
 
 		try (var mcpClient = clientBuilder.build()) {
 			InitializeResult initResult = mcpClient.initialize();
 			assertThat(initResult).isNotNull();
 		}
-		finally {
-			mcpServer.close();
-		}
 	}
 
 	// ---------------------------------------
@@ -208,7 +193,7 @@ class HttpServletStatelessIntegrationTests {
 			return completionResponse;
 		};
 
-		var mcpServer = McpServer.sync(mcpStatelessServerTransport)
+		McpServer.sync(mcpStatelessServerTransport)
 			.capabilities(ServerCapabilities.builder().completions().build())
 			.prompts(new McpStatelessServerFeatures.SyncPromptSpecification(Prompt.builder("code_review")
 				.title("Code review")
@@ -241,9 +226,6 @@ class HttpServletStatelessIntegrationTests {
 			assertThat(completeRequest.get().argument().value()).isEqualTo("py");
 			assertThat(completeRequest.get().ref().type()).isEqualTo(PromptReference.TYPE);
 		}
-		finally {
-			mcpServer.close();
-		}
 	}
 
 	@Test
@@ -265,7 +247,7 @@ class HttpServletStatelessIntegrationTests {
 				.of(PromptArgument.builder("topic").title("Topic").description("string").required(false).build()))
 			.build();
 
-		var mcpServer = McpServer.sync(mcpStatelessServerTransport)
+		McpServer.sync(mcpStatelessServerTransport)
 			.capabilities(ServerCapabilities.builder().completions().build())
 			.prompts(
 					new McpStatelessServerFeatures.SyncPromptSpecification(prompt,
@@ -291,9 +273,6 @@ class HttpServletStatelessIntegrationTests {
 			assertThat(result.completion().total()).isZero();
 			assertThat(result.completion().hasMore()).isFalse();
 		}
-		finally {
-			mcpServer.close();
-		}
 	}
 
 	@Test
@@ -313,7 +292,7 @@ class HttpServletStatelessIntegrationTests {
 			.mimeType("text/plain")
 			.build();
 
-		var mcpServer = McpServer.sync(mcpStatelessServerTransport)
+		McpServer.sync(mcpStatelessServerTransport)
 			.capabilities(ServerCapabilities.builder().completions().build())
 			.resourceTemplates(
 					new McpStatelessServerFeatures.SyncResourceTemplateSpecification(template,
@@ -339,14 +318,11 @@ class HttpServletStatelessIntegrationTests {
 			assertThat(result.completion().total()).isZero();
 			assertThat(result.completion().hasMore()).isFalse();
 		}
-		finally {
-			mcpServer.close();
-		}
 	}
 
 	@Test
 	void testCompletionForNonExistentPromptReturnsInvalidParams() {
-		var mcpServer = McpServer.sync(mcpStatelessServerTransport)
+		McpServer.sync(mcpStatelessServerTransport)
 			.capabilities(ServerCapabilities.builder().completions().build())
 			.build();
 
@@ -364,14 +340,11 @@ class HttpServletStatelessIntegrationTests {
 				.extracting(McpSchema.JSONRPCResponse.JSONRPCError::code)
 				.isEqualTo(ErrorCodes.INVALID_PARAMS);
 		}
-		finally {
-			mcpServer.close();
-		}
 	}
 
 	@Test
 	void testCompletionForNonExistentResourceReturnsResourceNotFound() {
-		var mcpServer = McpServer.sync(mcpStatelessServerTransport)
+		McpServer.sync(mcpStatelessServerTransport)
 			.capabilities(ServerCapabilities.builder().completions().build())
 			.build();
 
@@ -390,9 +363,6 @@ class HttpServletStatelessIntegrationTests {
 				.extracting(McpSchema.JSONRPCResponse.JSONRPCError::code)
 				.isEqualTo(McpSchema.ErrorCodes.RESOURCE_NOT_FOUND);
 		}
-		finally {
-			mcpServer.close();
-		}
 	}
 
 	// ---------------------------------------
@@ -421,7 +391,7 @@ class HttpServletStatelessIntegrationTests {
 						.build();
 				});
 
-		var mcpServer = McpServer.sync(mcpStatelessServerTransport)
+		McpServer.sync(mcpStatelessServerTransport)
 			.serverInfo("test-server", "1.0.0")
 			.capabilities(ServerCapabilities.builder().tools(true).build())
 			.tools(tool)
@@ -459,9 +429,6 @@ class HttpServletStatelessIntegrationTests {
 				.isEqualTo(json("""
 						{"result":5.0,"operation":"2 + 3","timestamp":"2024-01-01T10:00:00Z"}"""));
 		}
-		finally {
-			mcpServer.close();
-		}
 	}
 
 	@Test
@@ -492,7 +459,7 @@ class HttpServletStatelessIntegrationTests {
 			})
 			.build();
 
-		var mcpServer = McpServer.sync(mcpStatelessServerTransport)
+		McpServer.sync(mcpStatelessServerTransport)
 			.serverInfo("test-server", "1.0.0")
 			.capabilities(ServerCapabilities.builder().tools(true).build())
 			.tools(tool)
@@ -517,9 +484,6 @@ class HttpServletStatelessIntegrationTests {
 						{"name":"John","age":30}"""), json("""
 						{"name":"Peter","age":25}"""));
 		}
-		finally {
-			mcpServer.closeGracefully();
-		}
 	}
 
 	@Test
@@ -545,7 +509,7 @@ class HttpServletStatelessIntegrationTests {
 				.build())
 			.build();
 
-		var mcpServer = McpServer.sync(mcpStatelessServerTransport)
+		McpServer.sync(mcpStatelessServerTransport)
 			.serverInfo("test-server", "1.0.0")
 			.capabilities(ServerCapabilities.builder().tools(true).build())
 			.tools(tool)
@@ -572,9 +536,6 @@ class HttpServletStatelessIntegrationTests {
 					McpSchema.TextContent.builder("Error calling tool: Simulated in-handler error").build());
 			assertThat(response.structuredContent()).isNull();
 		}
-		finally {
-			mcpServer.closeGracefully();
-		}
 	}
 
 	@Test
@@ -599,7 +560,7 @@ class HttpServletStatelessIntegrationTests {
 						.build();
 				});
 
-		var mcpServer = McpServer.sync(mcpStatelessServerTransport)
+		McpServer.sync(mcpStatelessServerTransport)
 			.serverInfo("test-server", "1.0.0")
 			.capabilities(ServerCapabilities.builder().tools(true).build())
 			.tools(tool)
@@ -621,9 +582,6 @@ class HttpServletStatelessIntegrationTests {
 			String errorMessage = ((McpSchema.TextContent) response.content().get(0)).text();
 			assertThat(errorMessage).contains("Validation failed");
 		}
-		finally {
-			mcpServer.close();
-		}
 	}
 
 	@Test
@@ -643,7 +601,7 @@ class HttpServletStatelessIntegrationTests {
 					return CallToolResult.builder().addTextContent("Calculation completed").build();
 				});
 
-		var mcpServer = McpServer.sync(mcpStatelessServerTransport)
+		McpServer.sync(mcpStatelessServerTransport)
 			.serverInfo("test-server", "1.0.0")
 			.capabilities(ServerCapabilities.builder().tools(true).build())
 			.instructions("bla")
@@ -667,9 +625,6 @@ class HttpServletStatelessIntegrationTests {
 			assertThat(errorMessage).isEqualTo(
 					"Response missing structured content which is expected when calling tool with non-empty outputSchema");
 		}
-		finally {
-			mcpServer.close();
-		}
 	}
 
 	@Test
@@ -738,9 +693,6 @@ class HttpServletStatelessIntegrationTests {
 				.isEqualTo(json("""
 						{"count":3,"message":"Dynamic execution"}"""));
 		}
-		finally {
-			mcpServer.close();
-		}
 	}
 
 	@Test
@@ -787,13 +739,11 @@ class HttpServletStatelessIntegrationTests {
 		assertThat(jsonrpcResponse.error()).isNotNull();
 		assertThat(jsonrpcResponse.error().code()).isEqualTo(ErrorCodes.INTERNAL_ERROR);
 		assertThat(jsonrpcResponse.error().message()).isEqualTo("testing");
-
-		mcpServer.close();
 	}
 
 	@Test
 	void testMissingHandlerReturnsMethodNotFoundError() {
-		var mcpServer = McpServer.sync(mcpStatelessServerTransport)
+		McpServer.sync(mcpStatelessServerTransport)
 			.serverInfo("test-server", "1.0.0")
 			.capabilities(ServerCapabilities.builder().build())
 			.build();
@@ -828,9 +778,6 @@ class HttpServletStatelessIntegrationTests {
 			assertThat(response.get().error().code()).isEqualTo(McpSchema.ErrorCodes.METHOD_NOT_FOUND);
 			assertThat(response.get().error().message()).isEqualTo("Method not found: foo/bar");
 		}
-		finally {
-			mcpServer.closeGracefully();
-		}
 	}
 
 	@Test
@@ -841,7 +788,7 @@ class HttpServletStatelessIntegrationTests {
 		handlerLogger.addAppender(logAppender);
 
 		try {
-			var mcpServer = McpServer.sync(mcpStatelessServerTransport)
+			McpServer.sync(mcpStatelessServerTransport)
 				.serverInfo("test-server", "1.0.0")
 				.capabilities(ServerCapabilities.builder().build())
 				.build();
@@ -849,9 +796,6 @@ class HttpServletStatelessIntegrationTests {
 			try (var mcpClient = clientBuilder.build()) {
 				mcpClient.initialize(); // automatically sends notifications/initialized
 			}
-			finally {
-				mcpServer.close();
-			}
 		}
 		finally {
 			handlerLogger.detachAppender(logAppender);
@@ -869,7 +813,7 @@ class HttpServletStatelessIntegrationTests {
 		handlerLogger.addAppender(logAppender);
 
 		try {
-			var mcpServer = McpServer.sync(mcpStatelessServerTransport)
+			McpServer.sync(mcpStatelessServerTransport)
 				.serverInfo("test-server", "1.0.0")
 				.capabilities(ServerCapabilities.builder().build())
 				.build();
@@ -878,9 +822,7 @@ class HttpServletStatelessIntegrationTests {
 				mcpClient.initialize();
 				mcpClient.rootsListChangedNotification();
 			}
-			finally {
+
-				mcpServer.close();
-			}
 		}
 		finally {
 			handlerLogger.detachAppender(logAppender);
@@ -913,7 +855,7 @@ class HttpServletStatelessIntegrationTests {
 				.build())
 			.build();
 
-		var mcpServer = McpServer.sync(mcpStatelessServerTransport)
+		McpServer.sync(mcpStatelessServerTransport)
 			.capabilities(ServerCapabilities.builder().tools(false).build())
 			.tools(tool1)
 			.build();
@@ -929,16 +871,11 @@ class HttpServletStatelessIntegrationTests {
 				.isInstanceOf(RuntimeException.class)
 				.hasMessageContaining("413");
 		}
-		finally {
-			mcpServer.closeGracefully();
-		}
 	}
 
 	@Test
 	void rejectsWhenBodyBytesExceedLimitWithoutContentLengthHeader() throws Exception {
-		var mcpServer = McpServer.sync(mcpStatelessServerTransport).build();
+		McpServer.sync(mcpStatelessServerTransport).build();
-
-		try {
 		var httpClient = HttpClient.newHttpClient();
 
 		// A publisher with unknown content length forces chunked transfer
@@ -977,10 +914,6 @@ class HttpServletStatelessIntegrationTests {
 		var response = httpClient.send(request, HttpResponse.BodyHandlers.discarding());
 		assertThat(response.statusCode()).isEqualTo(HttpServletResponse.SC_REQUEST_ENTITY_TOO_LARGE);
 	}
-		finally {
-			mcpServer.closeGracefully();
-		}
-	}
 
 	private double evaluateExpression(String expression) {
 		// Simple expression evaluator for testing

mcp-test/src/test/java/io/modelcontextprotocol/server/HttpServletStatelessSharedIntegrationTests.java

@@ -20,7 +20,9 @@ import jakarta.servlet.http.HttpServletRequest;
 import org.apache.catalina.LifecycleException;
 import org.apache.catalina.LifecycleState;
 import org.apache.catalina.startup.Tomcat;
+import org.junit.jupiter.api.AfterAll;
 import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Timeout;
 import org.junit.jupiter.params.provider.Arguments;
@@ -40,29 +42,49 @@ class HttpServletStatelessSharedIntegrationTests extends AbstractStatelessIntegr
 	static McpTransportContextExtractor<HttpServletRequest> TEST_CONTEXT_EXTRACTOR = (request) -> McpTransportContext
 		.create(Map.of("important", "value"));
 
-	private HttpServletStatelessServerTransport mcpServerTransport;
+	// Tomcat is started once for the whole class; each test swaps in its own transport
+	private static final TomcatTestUtil.DelegatingServlet MCP_SERVLET = new TomcatTestUtil.DelegatingServlet();
 
-	private Tomcat tomcat;
+	private static Tomcat tomcat;
+
+	private HttpServletStatelessServerTransport mcpServerTransport;
 
 	static Stream<Arguments> clientsForTesting() {
 		return Stream.of(Arguments.of("httpclient"));
 	}
 
+	@BeforeAll
+	public static void beforeAll() {
+		tomcat = TomcatTestUtil.createTomcatServer("", PORT, MCP_SERVLET);
+		try {
+			tomcat.start();
+			assertThat(tomcat.getServer().getState()).isEqualTo(LifecycleState.STARTED);
+		}
+		catch (Exception e) {
+			throw new RuntimeException("Failed to start Tomcat", e);
+		}
+	}
+
+	@AfterAll
+	public static void afterAll() {
+		if (tomcat != null) {
+			try {
+				tomcat.stop();
+				tomcat.destroy();
+			}
+			catch (LifecycleException e) {
+				throw new RuntimeException("Failed to stop Tomcat", e);
+			}
+		}
+	}
+
 	@BeforeEach
 	public void before() {
 		this.mcpServerTransport = HttpServletStatelessServerTransport.builder()
 			.contextExtractor(TEST_CONTEXT_EXTRACTOR)
 			.messageEndpoint(MESSAGE_ENDPOINT)
 			.build();
-
+		MCP_SERVLET.setDelegate(this.mcpServerTransport);
-		this.tomcat = TomcatTestUtil.createTomcatServer("", PORT, this.mcpServerTransport);
-		try {
-			this.tomcat.start();
-			assertThat(this.tomcat.getServer().getState()).isEqualTo(LifecycleState.STARTED);
-		}
-		catch (Exception e) {
-			throw new RuntimeException("Failed to start Tomcat", e);
-		}
 
 		prepareClients(PORT, MESSAGE_ENDPOINT);
 	}
@@ -90,15 +112,6 @@ class HttpServletStatelessSharedIntegrationTests extends AbstractStatelessIntegr
 		if (this.mcpServerTransport != null) {
 			this.mcpServerTransport.closeGracefully().block();
 		}
-		if (this.tomcat != null) {
-			try {
-				this.tomcat.stop();
-				this.tomcat.destroy();
-			}
-			catch (LifecycleException e) {
-				throw new RuntimeException("Failed to stop Tomcat", e);
-			}
-		}
 	}
 
 }

mcp-test/src/test/java/io/modelcontextprotocol/server/HttpServletStreamableIntegrationTests.java

@@ -31,7 +31,9 @@ import org.apache.catalina.LifecycleException;
 import org.apache.catalina.LifecycleState;
 import org.apache.catalina.startup.Tomcat;
 import org.awaitility.Awaitility;
+import org.junit.jupiter.api.AfterAll;
 import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.Timeout;
@@ -48,14 +50,42 @@ class HttpServletStreamableIntegrationTests extends AbstractMcpClientServerInteg
 
 	private static final String MESSAGE_ENDPOINT = "/mcp/message";
 
-	private HttpServletStreamableServerTransportProvider mcpServerTransportProvider;
+	// Tomcat is started once for the whole class; each test swaps in its own transport
+	private static final TomcatTestUtil.DelegatingServlet MCP_SERVLET = new TomcatTestUtil.DelegatingServlet();
 
-	private Tomcat tomcat;
+	private static Tomcat tomcat;
+
+	private HttpServletStreamableServerTransportProvider mcpServerTransportProvider;
 
 	static Stream<Arguments> clientsForTesting() {
 		return Stream.of(Arguments.of("httpclient"));
 	}
 
+	@BeforeAll
+	public static void beforeAll() {
+		tomcat = TomcatTestUtil.createTomcatServer("", PORT, MCP_SERVLET);
+		try {
+			tomcat.start();
+			assertThat(tomcat.getServer().getState()).isEqualTo(LifecycleState.STARTED);
+		}
+		catch (Exception e) {
+			throw new RuntimeException("Failed to start Tomcat", e);
+		}
+	}
+
+	@AfterAll
+	public static void afterAll() {
+		if (tomcat != null) {
+			try {
+				tomcat.stop();
+				tomcat.destroy();
+			}
+			catch (LifecycleException e) {
+				throw new RuntimeException("Failed to stop Tomcat", e);
+			}
+		}
+	}
+
 	@BeforeEach
 	public void before() {
 		// Create and configure the transport provider
@@ -65,15 +95,7 @@ class HttpServletStreamableIntegrationTests extends AbstractMcpClientServerInteg
 			.keepAliveInterval(Duration.ofSeconds(1))
 			.maxRequestSize(MAX_REQUEST_SIZE)
 			.build();
-
+		MCP_SERVLET.setDelegate(mcpServerTransportProvider);
-		tomcat = TomcatTestUtil.createTomcatServer("", PORT, mcpServerTransportProvider);
-		try {
-			tomcat.start();
-			assertThat(tomcat.getServer().getState()).isEqualTo(LifecycleState.STARTED);
-		}
-		catch (Exception e) {
-			throw new RuntimeException("Failed to start Tomcat", e);
-		}
 
 		clientBuilders
 			.put("httpclient",
@@ -97,15 +119,6 @@ class HttpServletStreamableIntegrationTests extends AbstractMcpClientServerInteg
 		if (mcpServerTransportProvider != null) {
 			mcpServerTransportProvider.closeGracefully().block();
 		}
-		if (tomcat != null) {
-			try {
-				tomcat.stop();
-				tomcat.destroy();
-			}
-			catch (LifecycleException e) {
-				throw new RuntimeException("Failed to stop Tomcat", e);
-			}
-		}
 	}
 
 	@Test

mcp-test/src/test/java/io/modelcontextprotocol/server/McpCompletionTests.java

@@ -13,8 +13,8 @@ import org.apache.catalina.LifecycleException;
 import org.apache.catalina.LifecycleState;
 import org.apache.catalina.startup.Tomcat;
 
-import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.AfterAll;
-import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.Test;
 
 import io.modelcontextprotocol.client.McpClient;
@@ -48,19 +48,20 @@ import static org.assertj.core.api.InstanceOfAssertFactories.type;
  */
 class McpCompletionTests {
 
-	private HttpServletSseServerTransportProvider mcpServerTransportProvider;
-
 	private static final int PORT = TomcatTestUtil.findAvailablePort();
 
 	private static final String CUSTOM_MESSAGE_ENDPOINT = "/otherPath/mcp/message";
 
-	McpClient.SyncSpec clientBuilder;
+	private static HttpServletSseServerTransportProvider mcpServerTransportProvider;
 
-	private Tomcat tomcat;
+	private static Tomcat tomcat;
 
-	@BeforeEach
+	final McpClient.SyncSpec clientBuilder = McpClient
-	public void before() {
+		.sync(HttpClientSseClientTransport.builder("http://localhost:" + PORT).build());
-		// Create and con figure the transport provider
+
+	@BeforeAll
+	public static void beforeAll() {
+		// Create and configure the transport provider
 		mcpServerTransportProvider = HttpServletSseServerTransportProvider.builder()
 			.messageEndpoint(CUSTOM_MESSAGE_ENDPOINT)
 			.build();
@@ -73,12 +74,10 @@ class McpCompletionTests {
 		catch (Exception e) {
 			throw new RuntimeException("Failed to start Tomcat", e);
 		}
-
-		this.clientBuilder = McpClient.sync(HttpClientSseClientTransport.builder("http://localhost:" + PORT).build());
 	}
 
-	@AfterEach
+	@AfterAll
-	public void after() {
+	public static void afterAll() {
 		if (mcpServerTransportProvider != null) {
 			mcpServerTransportProvider.closeGracefully().block();
 		}
@@ -88,7 +87,7 @@ class McpCompletionTests {
 				tomcat.destroy();
 			}
 			catch (LifecycleException e) {
-				e.printStackTrace();
+				throw new RuntimeException("Failed to stop Tomcat", e);
 			}
 		}
 	}
@@ -109,7 +108,7 @@ class McpCompletionTests {
 			.size(123L)
 			.build();
 
-		var mcpServer = McpServer.sync(mcpServerTransportProvider)
+		McpServer.sync(mcpServerTransportProvider)
 			.capabilities(ServerCapabilities.builder().completions().build())
 			.resources(new McpServerFeatures.SyncResourceSpecification(resource,
 					(exchange, req) -> ReadResourceResult.builder(List.of()).build()))
@@ -135,8 +134,6 @@ class McpCompletionTests {
 			assertThat(receivedRequest.get().context().arguments()).containsEntry("previous", "value");
 			assertThat(result.completion().values()).containsExactly("test-completion");
 		}
-
-		mcpServer.close();
 	}
 
 	@Test
@@ -153,7 +150,7 @@ class McpCompletionTests {
 			.arguments(List.of(PromptArgument.builder("arg").description("string").required(false).build()))
 			.build();
 
-		var mcpServer = McpServer.sync(mcpServerTransportProvider)
+		McpServer.sync(mcpServerTransportProvider)
 			.capabilities(ServerCapabilities.builder().completions().build())
 			.prompts(new McpServerFeatures.SyncPromptSpecification(prompt,
 					(mcpSyncServerExchange, getPromptRequest) -> null))
@@ -178,8 +175,6 @@ class McpCompletionTests {
 			assertThat(contextWasNull.get()).isTrue();
 			assertThat(result.completion().values()).containsExactly("no-context-completion");
 		}
-
-		mcpServer.close();
 	}
 
 	@Test
@@ -197,7 +192,7 @@ class McpCompletionTests {
 			.arguments(List.of(PromptArgument.builder("topic").description("string").required(false).build()))
 			.build();
 
-		var mcpServer = McpServer.sync(mcpServerTransportProvider)
+		McpServer.sync(mcpServerTransportProvider)
 			.capabilities(ServerCapabilities.builder().completions().build())
 			.prompts(
 					new McpServerFeatures.SyncPromptSpecification(prompt,
@@ -224,8 +219,6 @@ class McpCompletionTests {
 			assertThat(result.completion().total()).isZero();
 			assertThat(result.completion().hasMore()).isFalse();
 		}
-
-		mcpServer.close();
 	}
 
 	@Test
@@ -243,7 +236,7 @@ class McpCompletionTests {
 			.mimeType("text/plain")
 			.build();
 
-		var mcpServer = McpServer.sync(mcpServerTransportProvider)
+		McpServer.sync(mcpServerTransportProvider)
 			.capabilities(ServerCapabilities.builder().completions().build())
 			.resourceTemplates(
 					new McpServerFeatures.SyncResourceTemplateSpecification(template,
@@ -271,13 +264,11 @@ class McpCompletionTests {
 			assertThat(result.completion().total()).isZero();
 			assertThat(result.completion().hasMore()).isFalse();
 		}
-
-		mcpServer.close();
 	}
 
 	@Test
 	void testCompletionForNonExistentPromptReturnsInvalidParams() {
-		var mcpServer = McpServer.sync(mcpServerTransportProvider)
+		McpServer.sync(mcpServerTransportProvider)
 			.capabilities(ServerCapabilities.builder().completions().build())
 			.build();
 
@@ -297,13 +288,11 @@ class McpCompletionTests {
 				.extracting(McpSchema.JSONRPCResponse.JSONRPCError::code)
 				.isEqualTo(ErrorCodes.INVALID_PARAMS);
 		}
-
-		mcpServer.close();
 	}
 
 	@Test
 	void testCompletionForNonExistentResourceReturnsResourceNotFound() {
-		var mcpServer = McpServer.sync(mcpServerTransportProvider)
+		McpServer.sync(mcpServerTransportProvider)
 			.capabilities(ServerCapabilities.builder().completions().build())
 			.build();
 
@@ -324,8 +313,6 @@ class McpCompletionTests {
 				.extracting(McpSchema.JSONRPCResponse.JSONRPCError::code)
 				.isEqualTo(McpSchema.ErrorCodes.RESOURCE_NOT_FOUND);
 		}
-
-		mcpServer.close();
 	}
 
 	@Test
@@ -364,7 +351,7 @@ class McpCompletionTests {
 			.size(456L)
 			.build();
 
-		var mcpServer = McpServer.sync(mcpServerTransportProvider)
+		McpServer.sync(mcpServerTransportProvider)
 			.capabilities(ServerCapabilities.builder().completions().build())
 			.resources(new McpServerFeatures.SyncResourceSpecification(resource,
 					(exchange, req) -> ReadResourceResult.builder(List.of()).build()))
@@ -407,8 +394,6 @@ class McpCompletionTests {
 			CompleteResult tableResult2 = mcpClient.completeCompletion(tableRequest2);
 			assertThat(tableResult2.completion().values()).containsExactly("products", "categories", "inventory");
 		}
-
-		mcpServer.close();
 	}
 
 	@Test
@@ -443,7 +428,7 @@ class McpCompletionTests {
 			.size(456L)
 			.build();
 
-		var mcpServer = McpServer.sync(mcpServerTransportProvider)
+		McpServer.sync(mcpServerTransportProvider)
 			.capabilities(ServerCapabilities.builder().completions().build())
 			.resources(new McpServerFeatures.SyncResourceSpecification(resource,
 					(exchange, req) -> ReadResourceResult.builder(List.of()).build()))
@@ -477,8 +462,6 @@ class McpCompletionTests {
 			CompleteResult resultWithContext = mcpClient.completeCompletion(requestWithContext);
 			assertThat(resultWithContext.completion().values()).containsExactly("users", "orders", "products");
 		}
-
-		mcpServer.close();
 	}
 
 	@Test
@@ -488,7 +471,7 @@ class McpCompletionTests {
 
 		McpSchema.Prompt prompt = Prompt.builder("test-prompt").description("this is a test prompt").build();
 
-		var mcpServer = McpServer.sync(mcpServerTransportProvider)
+		McpServer.sync(mcpServerTransportProvider)
 			.capabilities(ServerCapabilities.builder().completions().build())
 			.prompts(new McpServerFeatures.SyncPromptSpecification(prompt,
 					(mcpSyncServerExchange, getPromptRequest) -> null))
@@ -510,8 +493,6 @@ class McpCompletionTests {
 			CompleteResult completeResult = mcpClient.completeCompletion(request);
 			assertThat(completeResult.completion().values()).isEmpty();
 		}
-
-		mcpServer.close();
 	}
 
 }

mcp-test/src/test/java/io/modelcontextprotocol/server/transport/TomcatTestUtil.java

@@ -10,6 +10,10 @@ import java.net.ServerSocket;
 
 import jakarta.servlet.Filter;
 import jakarta.servlet.Servlet;
+import jakarta.servlet.ServletConfig;
+import jakarta.servlet.ServletException;
+import jakarta.servlet.ServletRequest;
+import jakarta.servlet.ServletResponse;
 import org.apache.catalina.Context;
 import org.apache.catalina.startup.Tomcat;
 import org.apache.tomcat.util.descriptor.web.FilterDef;
@@ -63,6 +67,57 @@ public class TomcatTestUtil {
 		return tomcat;
 	}
 
+	/**
+	 * A servlet forwarding all requests to a delegate that can be swapped between tests.
+	 * Register one with {@link #createTomcatServer} to start Tomcat once per test class
+	 * while still handing each test a freshly built transport.
+	 */
+	public static class DelegatingServlet implements Servlet {
+
+		private volatile ServletConfig servletConfig;
+
+		private volatile Servlet delegate;
+
+		/**
+		 * Sets the servlet handling subsequent requests. The delegate is not
+		 * {@link Servlet#init(ServletConfig) initialized}, since the MCP servlet
+		 * transports do not rely on their {@link ServletConfig}.
+		 */
+		public void setDelegate(Servlet delegate) {
+			this.delegate = delegate;
+		}
+
+		@Override
+		public void init(ServletConfig config) {
+			this.servletConfig = config;
+		}
+
+		@Override
+		public ServletConfig getServletConfig() {
+			return this.servletConfig;
+		}
+
+		@Override
+		public void service(ServletRequest request, ServletResponse response) throws ServletException, IOException {
+			var current = this.delegate;
+			if (current == null) {
+				throw new IllegalStateException("No delegate servlet has been set");
+			}
+			current.service(request, response);
+		}
+
+		@Override
+		public String getServletInfo() {
+			return DelegatingServlet.class.getSimpleName();
+		}
+
+		@Override
+		public void destroy() {
+			this.delegate = null;
+		}
+
+	}
+
 	/**
 	 * Finds an available port on the local machine.
 	 * @return an available port number