Add simple StdioServerTransportTest

Author: tzolov

mcp/src/main/java/spring/ai/experimental/mcp/client/stdio/StdioServerTransport.java

@@ -41,7 +41,7 @@ public class StdioServerTransport extends AbstractMcpTransport {
 	private Scheduler outboundScheduler;
 	private Scheduler errorScheduler;
 
-	private volatile boolean isRunning;
+	volatile boolean isRunning;
 
 	private final ServerParameters params;
 
@@ -74,7 +74,8 @@ public void start() {
 		fullCommand.add(params.getCommand());
 		fullCommand.addAll(params.getArgs());
 
-		ProcessBuilder processBuilder = new ProcessBuilder(fullCommand);
+		ProcessBuilder processBuilder = this.getProcessBuilder();
+		processBuilder.command(fullCommand);
 		processBuilder.environment().putAll(params.getEnv());
 
 		// Start the process
@@ -102,6 +103,10 @@ public void start() {
 		startErrorProcessing();
 	}
 
+	protected ProcessBuilder getProcessBuilder() {
+		return new ProcessBuilder();
+	}
+
 	public void awaitForExit() {
 		try {
 			this.process.waitFor();

mcp/src/test/java/spring/ai/experimental/mcp/client/stdio/StdioServerTransportTests.java

@@ -0,0 +1,132 @@
+/*
+ * Copyright 2024 - 2024 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package spring.ai.experimental.mcp.client.stdio;
+
+import java.io.BufferedReader;
+import java.io.BufferedWriter;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+/**
+ * @author Christian Tzolov
+ *
+ */
+public class StdioServerTransportTests {
+
+	@Mock
+	private ServerParameters mockParams;
+
+	@Mock
+	private Process mockProcess;
+
+	@Mock
+	private BufferedReader mockErrorReader;
+
+	@Mock
+	private BufferedReader mockReader;
+
+	@Mock
+	private BufferedWriter mockWriter;
+
+	@Mock
+	ProcessBuilder mockProcessBuilder;
+
+	private StdioServerTransport stdioServerTransport;
+
+	@BeforeEach
+	public void setUp() {
+		MockitoAnnotations.openMocks(this);
+		when(mockParams.getCommand()).thenReturn("dummyCommand");
+		when(mockParams.getArgs()).thenReturn(List.of("arg1", "arg2"));
+		when(mockParams.getEnv()).thenReturn(new HashMap<>(Map.of("key", "value")));
+		stdioServerTransport = new StdioServerTransport(mockParams, new ObjectMapper()) {
+			@Override
+			protected ProcessBuilder getProcessBuilder() {
+				return mockProcessBuilder;
+			}
+		};
+	}
+
+	@Test
+	public void testStart_Success() throws IOException {
+		// Arrange
+		when(mockProcessBuilder.start()).thenReturn(mockProcess);
+		when(mockProcess.getInputStream()).thenReturn(mock(InputStream.class));
+		when(mockProcess.getOutputStream()).thenReturn(mock(OutputStream.class));
+		when(mockProcess.errorReader()).thenReturn(mockErrorReader);
+		when(mockProcess.inputReader()).thenReturn(mockReader);
+		when(mockProcess.outputWriter()).thenReturn(mockWriter);
+
+		// Act
+		stdioServerTransport.start();
+
+		// Assert
+		// TODO: assertThat(stdioServerTransport.isRunning).isTrue();
+		verify(mockProcessBuilder).start();
+	}
+
+	@Test
+	public void testStart_ProcessStartFailure() throws IOException {
+		// Arrange
+		when(mockProcessBuilder.start()).thenThrow(new IOException("Failed to start process"));
+
+		// Act & Assert
+		RuntimeException exception = assertThrows(RuntimeException.class, () -> stdioServerTransport.start());
+		assertThat(exception.getMessage()).contains("Failed to start process with command");
+	}
+
+	@Test
+	public void testStart_NullInputStream() throws IOException {
+		// Arrange
+		when(mockProcessBuilder.start()).thenReturn(mockProcess);
+		when(mockProcess.getInputStream()).thenReturn(null);
+		when(mockProcess.getOutputStream()).thenReturn(mock(OutputStream.class));
+
+		// Act & Assert
+		RuntimeException exception = assertThrows(RuntimeException.class, () -> stdioServerTransport.start());
+		assertThat(exception.getMessage()).contains("Process input or output stream is null");
+		verify(mockProcess).destroy();
+	}
+
+	@Test
+	public void testStart_NullOutputStream() throws IOException {
+		// Arrange
+		when(mockProcessBuilder.start()).thenReturn(mockProcess);
+		when(mockProcess.getInputStream()).thenReturn(mock(InputStream.class));
+		when(mockProcess.getOutputStream()).thenReturn(null);
+
+		// Act & Assert
+		RuntimeException exception = assertThrows(RuntimeException.class, () -> stdioServerTransport.start());
+		assertThat(exception.getMessage()).contains("Process input or output stream is null");
+		verify(mockProcess).destroy();
+	}
+}