feat(test): adds findAvailablePort for test server

Author: Aliaksie

mcp/src/test/java/io/modelcontextprotocol/server/transport/HttpServletSseServerCustomContextPathTests.java

@@ -4,11 +4,11 @@
 package io.modelcontextprotocol.server.transport;
 
 import com.fasterxml.jackson.databind.ObjectMapper;
+
 import io.modelcontextprotocol.client.McpClient;
 import io.modelcontextprotocol.client.transport.HttpClientSseClientTransport;
 import io.modelcontextprotocol.server.McpServer;
 import io.modelcontextprotocol.spec.McpSchema;
-import org.apache.catalina.Context;
 import org.apache.catalina.LifecycleException;
 import org.apache.catalina.LifecycleState;
 import org.apache.catalina.startup.Tomcat;
@@ -18,9 +18,9 @@
 
 import static org.assertj.core.api.Assertions.assertThat;
 
-public class HttpServletSseServerCustomContextPathTests {
+class HttpServletSseServerCustomContextPathTests {
 
-	private static final int PORT = 8195;
+	private static final int PORT = TomcatTestUtil.findAvailablePort();
 
 	private static final String CUSTOM_CONTEXT_PATH = "/api/v1";
 
@@ -49,7 +49,7 @@ public void before() {
 
 		try {
 			tomcat.start();
-			assertThat(tomcat.getServer().getState() == LifecycleState.STARTED);
+			assertThat(tomcat.getServer().getState()).isEqualTo(LifecycleState.STARTED);
 		}
 		catch (Exception e) {
 			throw new RuntimeException("Failed to start Tomcat", e);

mcp/src/test/java/io/modelcontextprotocol/server/transport/HttpServletSseServerTransportProviderIntegrationTests.java

@@ -10,6 +10,7 @@
 import java.util.function.Function;
 
 import com.fasterxml.jackson.databind.ObjectMapper;
+
 import io.modelcontextprotocol.client.McpClient;
 import io.modelcontextprotocol.client.transport.HttpClientSseClientTransport;
 import io.modelcontextprotocol.server.McpServer;
@@ -42,9 +43,9 @@
 import static org.awaitility.Awaitility.await;
 import static org.mockito.Mockito.mock;
 
-public class HttpServletSseServerTransportProviderIntegrationTests {
+class HttpServletSseServerTransportProviderIntegrationTests {
 
-	private static final int PORT = 8185;
+	private static final int PORT = TomcatTestUtil.findAvailablePort();
 
 	private static final String CUSTOM_SSE_ENDPOINT = "/somePath/sse";
 
@@ -68,7 +69,7 @@ public void before() {
 		tomcat = TomcatTestUtil.createTomcatServer("", PORT, mcpServerTransportProvider);
 		try {
 			tomcat.start();
-			assertThat(tomcat.getServer().getState() == LifecycleState.STARTED);
+			assertThat(tomcat.getServer().getState()).isEqualTo(LifecycleState.STARTED);
 		}
 		catch (Exception e) {
 			throw new RuntimeException("Failed to start Tomcat", e);
@@ -127,7 +128,7 @@ void testCreateMessageWithoutSamplingCapabilities() {
 	}
 
 	@Test
-	void testCreateMessageSuccess() throws InterruptedException {
+	void testCreateMessageSuccess() {
 
 		// Client
 
@@ -185,8 +186,7 @@ void testCreateMessageSuccess() throws InterruptedException {
 
 		CallToolResult response = mcpClient.callTool(new McpSchema.CallToolRequest("tool1", Map.of()));
 
-		assertThat(response).isNotNull();
-		assertThat(response).isEqualTo(callResponse);
+		assertThat(response).isNotNull().isEqualTo(callResponse);
 
 		mcpClient.close();
 		mcpServer.close();
@@ -395,8 +395,7 @@ void testToolCallSuccess() {
 
 		CallToolResult response = mcpClient.callTool(new McpSchema.CallToolRequest("tool1", Map.of()));
 
-		assertThat(response).isNotNull();
-		assertThat(response).isEqualTo(callResponse);
+		assertThat(response).isNotNull().isEqualTo(callResponse);
 
 		mcpClient.close();
 		mcpServer.close();

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

@@ -3,19 +3,23 @@
 */
 package io.modelcontextprotocol.server.transport;
 
-import com.fasterxml.jackson.databind.ObjectMapper;
+import java.io.IOException;
+import java.net.InetSocketAddress;
+import java.net.ServerSocket;
+
 import jakarta.servlet.Servlet;
 import org.apache.catalina.Context;
-import org.apache.catalina.LifecycleState;
 import org.apache.catalina.startup.Tomcat;
 
-import static org.junit.Assert.assertThat;
-
 /**
  * @author Christian Tzolov
  */
 public class TomcatTestUtil {
 
+	TomcatTestUtil() {
+		// Prevent instantiation
+	}
+
 	public static Tomcat createTomcatServer(String contextPath, int port, Servlet servlet) {
 
 		var tomcat = new Tomcat();
@@ -24,7 +28,6 @@ public static Tomcat createTomcatServer(String contextPath, int port, Servlet se
 		String baseDir = System.getProperty("java.io.tmpdir");
 		tomcat.setBaseDir(baseDir);
 
-		// Context context = tomcat.addContext("", baseDir);
 		Context context = tomcat.addContext(contextPath, baseDir);
 
 		// Add transport servlet to Tomcat
@@ -42,4 +45,19 @@ public static Tomcat createTomcatServer(String contextPath, int port, Servlet se
 		return tomcat;
 	}
 
+	/**
+	 * Finds an available port on the local machine.
+	 * @return an available port number
+	 * @throws IllegalStateException if no available port can be found
+	 */
+	public static int findAvailablePort() {
+		try (final ServerSocket socket = new ServerSocket()) {
+			socket.bind(new InetSocketAddress(0));
+			return socket.getLocalPort();
+		}
+		catch (final IOException e) {
+			throw new IllegalStateException("Cannot bind to an available port!", e);
+		}
+	}
+
 }