Improve stdio test Windows compatibility and refactor command logic

src/client/stdio.test.ts

@@ -1,9 +1,7 @@
 import { JSONRPCMessage } from "../types.js";
-import { StdioClientTransport, StdioServerParameters } from "./stdio.js";
+import { StdioClientTransport, getDefaultServerParameters } from "./stdio.js";
 
-const serverParameters: StdioServerParameters = {
-  command: "/usr/bin/tee",
-};
+const serverParameters = getDefaultServerParameters();
 
 test("should start then close cleanly", async () => {
   const client = new StdioClientTransport(serverParameters);

src/client/stdio.ts

@@ -39,6 +39,15 @@ export type StdioServerParameters = {
   cwd?: string;
 };
 
+// Configure default server parameters based on OS
+// Uses 'more' command for Windows and 'tee' command for Unix/Linux
+export const getDefaultServerParameters = (): StdioServerParameters => {
+  if (process.platform === "win32") {
+    return { command: "more" };
+  }
+  return { command: "/usr/bin/tee" };
+};
+
 /**
  * Environment variables to inherit by default, if an environment is not explicitly given.
  */

src/inMemory.test.ts

@@ -69,10 +69,43 @@ describe("InMemoryTransport", () => {
   });
 
   test("should throw error when sending after close", async () => {
-    await clientTransport.close();
+    const [client, server] = InMemoryTransport.createLinkedPair();
+    let clientError: Error | undefined;
+    let serverError: Error | undefined;
+
+    client.onerror = (err) => {
+      clientError = err;
+    };
+
+    server.onerror = (err) => {
+      serverError = err;
+    };
+
+    await client.close();
+
+    // Attempt to send message from client
     await expect(
-      clientTransport.send({ jsonrpc: "2.0", method: "test", id: 1 }),
+      client.send({
+        jsonrpc: "2.0",
+        method: "test",
+        id: 1,
+      }),
     ).rejects.toThrow("Not connected");
+
+    // Attempt to send message from server
+    await expect(
+      server.send({
+        jsonrpc: "2.0",
+        method: "test",
+        id: 2,
+      }),
+    ).rejects.toThrow("Not connected");
+
+    // Verify that both sides received errors
+    expect(clientError).toBeDefined();
+    expect(clientError?.message).toBe("Not connected");
+    expect(serverError).toBeDefined();
+    expect(serverError?.message).toBe("Not connected");
   });
 
   test("should queue messages sent before start", async () => {
@@ -91,4 +124,65 @@ describe("InMemoryTransport", () => {
     await serverTransport.start();
     expect(receivedMessage).toEqual(message);
   });
+
+  describe("error handling", () => {
+    test("should trigger onerror when sending without connection", async () => {
+      const transport = new InMemoryTransport();
+      let error: Error | undefined;
+
+      transport.onerror = (err) => {
+        error = err;
+      };
+
+      await expect(
+        transport.send({
+          jsonrpc: "2.0",
+          method: "test",
+          id: 1,
+        }),
+      ).rejects.toThrow("Not connected");
+
+      expect(error).toBeDefined();
+      expect(error?.message).toBe("Not connected");
+    });
+
+    test("should trigger onerror when sending after close", async () => {
+      const [client, server] = InMemoryTransport.createLinkedPair();
+      let clientError: Error | undefined;
+      let serverError: Error | undefined;
+
+      client.onerror = (err) => {
+        clientError = err;
+      };
+
+      server.onerror = (err) => {
+        serverError = err;
+      };
+
+      await client.close();
+
+      // Attempt to send message from client
+      await expect(
+        client.send({
+          jsonrpc: "2.0",
+          method: "test",
+          id: 1,
+        }),
+      ).rejects.toThrow("Not connected");
+
+      // Attempt to send message from server
+      await expect(
+        server.send({
+          jsonrpc: "2.0",
+          method: "test",
+          id: 2,
+        }),
+      ).rejects.toThrow("Not connected");
+
+      // Verify that both sides received errors
+      expect(clientError?.message).toBe("Not connected");
+      expect(serverError).toBeDefined();
+      expect(serverError?.message).toBe("Not connected");
+    });
+  });
 });

src/inMemory.ts

@@ -43,7 +43,9 @@ export class InMemoryTransport implements Transport {
 
   async send(message: JSONRPCMessage): Promise<void> {
     if (!this._otherTransport) {
-      throw new Error("Not connected");
+      const error = new Error("Not connected");
+      this.onerror?.(error);
+      throw error;
     }
 
     if (this._otherTransport.onmessage) {