initial client implementation

src/client/streamableHttp.test.ts

@@ -0,0 +1,194 @@
+import { StreamableHTTPClientTransport } from "./streamableHttp.js";
+import { JSONRPCMessage } from "../types.js";
+
+
+describe("StreamableHTTPClientTransport", () => {
+  let transport: StreamableHTTPClientTransport;
+
+  beforeEach(() => {
+    transport = new StreamableHTTPClientTransport(new URL("http://localhost:1234/mcp"));
+    jest.spyOn(global, "fetch");
+  });
+
+  afterEach(() => {
+    jest.clearAllMocks();
+  });
+
+  it("should send JSON-RPC messages via POST", async () => {
+    const message: JSONRPCMessage = {
+      jsonrpc: "2.0",
+      method: "test",
+      params: {},
+      id: "test-id"
+    };
+
+    (global.fetch as jest.Mock).mockResolvedValueOnce({
+      ok: true,
+      status: 202,
+      headers: new Headers(),
+    });
+
+    await transport.send(message);
+
+    expect(global.fetch).toHaveBeenCalledWith(
+      expect.anything(),
+      expect.objectContaining({
+        method: "POST",
+        headers: expect.any(Headers),
+        body: JSON.stringify(message)
+      })
+    );
+  });
+
+  it("should send batch messages", async () => {
+    const messages: JSONRPCMessage[] = [
+      { jsonrpc: "2.0", method: "test1", params: {}, id: "id1" },
+      { jsonrpc: "2.0", method: "test2", params: {}, id: "id2" }
+    ];
+
+    (global.fetch as jest.Mock).mockResolvedValueOnce({
+      ok: true,
+      status: 200,
+      headers: new Headers({ "content-type": "text/event-stream" }),
+      body: null
+    });
+
+    await transport.send(messages);
+
+    expect(global.fetch).toHaveBeenCalledWith(
+      expect.anything(),
+      expect.objectContaining({
+        method: "POST",
+        headers: expect.any(Headers),
+        body: JSON.stringify(messages)
+      })
+    );
+  });
+
+  it("should store session ID received during initialization", async () => {
+    const message: JSONRPCMessage = {
+      jsonrpc: "2.0",
+      method: "initialize",
+      params: {
+        clientInfo: { name: "test-client", version: "1.0" },
+        protocolVersion: "2025-03-26"
+      },
+      id: "init-id"
+    };
+
+    (global.fetch as jest.Mock).mockResolvedValueOnce({
+      ok: true,
+      status: 200,
+      headers: new Headers({ "mcp-session-id": "test-session-id" }),
+    });
+
+    await transport.send(message);
+
+    // Send a second message that should include the session ID
+    (global.fetch as jest.Mock).mockResolvedValueOnce({
+      ok: true,
+      status: 202,
+      headers: new Headers()
+    });
+
+    await transport.send({ jsonrpc: "2.0", method: "test", params: {} } as JSONRPCMessage);
+
+    // Check that second request included session ID header
+    const calls = (global.fetch as jest.Mock).mock.calls;
+    const lastCall = calls[calls.length - 1];
+    expect(lastCall[1].headers).toBeDefined();
+    expect(lastCall[1].headers.get("mcp-session-id")).toBe("test-session-id");
+  });
+
+  it("should handle 404 response when session expires", async () => {
+    const message: JSONRPCMessage = {
+      jsonrpc: "2.0",
+      method: "test",
+      params: {},
+      id: "test-id"
+    };
+
+    (global.fetch as jest.Mock).mockResolvedValueOnce({
+      ok: false,
+      status: 404,
+      statusText: "Not Found",
+      text: () => Promise.resolve("Session not found"),
+      headers: new Headers()
+    });
+
+    const errorSpy = jest.fn();
+    transport.onerror = errorSpy;
+
+    await expect(transport.send(message)).rejects.toThrow("Error POSTing to endpoint (HTTP 404)");
+    expect(errorSpy).toHaveBeenCalled();
+  });
+
+  it("should handle session termination via DELETE request", async () => {
+    // First set the session ID by mocking initialization
+    (global.fetch as jest.Mock).mockResolvedValueOnce({
+      ok: true,
+      status: 200,
+      headers: new Headers({ "mcp-session-id": "session-to-terminate" }),
+    });
+
+    await transport.send({
+      jsonrpc: "2.0",
+      method: "initialize",
+      params: {
+        clientInfo: { name: "test-client", version: "1.0" },
+        protocolVersion: "2025-03-26"
+      },
+      id: "init-id"
+    } as JSONRPCMessage);
+
+    // Mock DELETE request for session termination
+    (global.fetch as jest.Mock).mockResolvedValueOnce({
+      ok: true,
+      status: 200,
+      headers: new Headers()
+    });
+
+    const closeSpy = jest.fn();
+    transport.onclose = closeSpy;
+
+    await transport.close();
+
+    // Check that DELETE request was sent
+    const calls = (global.fetch as jest.Mock).mock.calls;
+    const lastCall = calls[calls.length - 1];
+    expect(lastCall[1].method).toBe("DELETE");
+    // The headers may be a plain object in tests
+    expect(lastCall[1].headers["mcp-session-id"]).toBe("session-to-terminate");
+
+    expect(closeSpy).toHaveBeenCalled();
+  });
+
+  it("should handle non-streaming JSON response", async () => {
+    const message: JSONRPCMessage = {
+      jsonrpc: "2.0",
+      method: "test",
+      params: {},
+      id: "test-id"
+    };
+
+    const responseMessage: JSONRPCMessage = {
+      jsonrpc: "2.0",
+      result: { success: true },
+      id: "test-id"
+    };
+
+    (global.fetch as jest.Mock).mockResolvedValueOnce({
+      ok: true,
+      status: 200,
+      headers: new Headers({ "content-type": "application/json" }),
+      json: () => Promise.resolve(responseMessage)
+    });
+
+    const messageSpy = jest.fn();
+    transport.onmessage = messageSpy;
+
+    await transport.send(message);
+
+    expect(messageSpy).toHaveBeenCalledWith(responseMessage);
+  });
+});