test: fix race conditions and re-enable disabled tests

- Re-enable previously disabled `testSessionClose()` tests in resiliency test suites
- Remove unused `@Disabled` import from WebClientStreamableHttpTransportErrorHandlingTest
- Fix race condition in async client tests by not advertising roots capability during initialization
  - Prevents server from listing roots during init which could cause timing issues when disconnecting immediately after initialization
- Applied fix to AbstractMcpAsyncClientResiliencyTests (both mcp and mcp-test modules) and HttpSseMcpAsyncClientLostConnectionTests

Signed-off-by: Christian Tzolov <[email protected]>

Author: tzolov

mcp-spring/mcp-spring-webflux/src/test/java/io/modelcontextprotocol/client/transport/WebClientStreamableHttpTransportErrorHandlingTest.java

@@ -20,7 +20,6 @@
 
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
-import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.Timeout;
 import org.springframework.web.reactive.function.client.WebClient;

mcp-test/src/main/java/io/modelcontextprotocol/client/AbstractMcpAsyncClientResiliencyTests.java

@@ -135,10 +135,13 @@ McpAsyncClient client(McpClientTransport transport, Function<McpClient.AsyncSpec
 		AtomicReference<McpAsyncClient> client = new AtomicReference<>();
 
 		assertThatCode(() -> {
+			// Do not advertise roots. Otherwise, the server will list roots during
+			// initialization. The client responds asynchronously, and there might be a
+			// rest condition in tests where we disconnect right after initialization.
 			McpClient.AsyncSpec builder = McpClient.async(transport)
 				.requestTimeout(getRequestTimeout())
 				.initializationTimeout(getInitializationTimeout())
-				.capabilities(McpSchema.ClientCapabilities.builder().roots(true).build());
+				.capabilities(McpSchema.ClientCapabilities.builder().build());
 			builder = customizer.apply(builder);
 			client.set(builder.build());
 		}).doesNotThrowAnyException();
@@ -212,7 +215,6 @@ void testCallTool() {
 	}
 
 	@Test
-	@Disabled("Temporarily disabled")
 	void testSessionClose() {
 		withClient(createMcpTransport(), mcpAsyncClient -> {
 			StepVerifier.create(mcpAsyncClient.initialize()).expectNextCount(1).verifyComplete();

mcp/src/test/java/io/modelcontextprotocol/client/AbstractMcpAsyncClientResiliencyTests.java

@@ -136,10 +136,13 @@ McpAsyncClient client(McpClientTransport transport, Function<McpClient.AsyncSpec
 		AtomicReference<McpAsyncClient> client = new AtomicReference<>();
 
 		assertThatCode(() -> {
+			// Do not advertise roots. Otherwise, the server will list roots during
+			// initialization. The client responds asynchronously, and there might be a
+			// rest condition in tests where we disconnect right after initialization.
 			McpClient.AsyncSpec builder = McpClient.async(transport)
 				.requestTimeout(getRequestTimeout())
 				.initializationTimeout(getInitializationTimeout())
-				.capabilities(McpSchema.ClientCapabilities.builder().roots(true).build());
+				.capabilities(McpSchema.ClientCapabilities.builder().build());
 			builder = customizer.apply(builder);
 			client.set(builder.build());
 		}).doesNotThrowAnyException();
@@ -213,7 +216,6 @@ void testCallTool() {
 	}
 
 	@Test
-	@Disabled("Temporarily disabled")
 	void testSessionClose() {
 		withClient(createMcpTransport(), mcpAsyncClient -> {
 			StepVerifier.create(mcpAsyncClient.initialize()).expectNextCount(1).verifyComplete();

mcp/src/test/java/io/modelcontextprotocol/client/HttpSseMcpAsyncClientLostConnectionTests.java

@@ -98,6 +98,9 @@ McpAsyncClient client(McpClientTransport transport) {
 		AtomicReference<McpAsyncClient> client = new AtomicReference<>();
 
 		assertThatCode(() -> {
+			// Do not advertise roots. Otherwise, the server will list roots during
+			// initialization. The client responds asynchronously, and there might be a
+			// rest condition in tests where we disconnect right after initialization.
 			McpClient.AsyncSpec builder = McpClient.async(transport)
 				.requestTimeout(Duration.ofSeconds(14))
 				.initializationTimeout(Duration.ofSeconds(2))