feat(web): persistent workspace terminal across tab switches

apps/next/tests/component/xterm-session.test.tsx

@@ -3,10 +3,15 @@ import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
 
 import { XtermSession } from '../../src/components/agent-workspace/xterm-session';
 
-const { openSpy, wsInstances, fetchSpy } = vi.hoisted(() => ({
+const { openSpy, wsInstances, fetchSpy, fitSpy } = vi.hoisted(() => ({
   openSpy: vi.fn(),
-  wsInstances: [] as Array<{ url: string }>,
+  wsInstances: [] as Array<{
+    url: string;
+    send: ReturnType<typeof vi.fn>;
+    close: ReturnType<typeof vi.fn>;
+  }>,
   fetchSpy: vi.fn(),
+  fitSpy: vi.fn(),
 }));
 
 class FakeTerminal {
@@ -30,7 +35,7 @@ class FakeTerminal {
 vi.mock('@xterm/xterm', () => ({ Terminal: FakeTerminal }));
 vi.mock('@xterm/addon-fit', () => ({
   FitAddon: class {
-    fit = vi.fn();
+    fit = fitSpy;
   },
 }));
 vi.mock('@xterm/addon-web-links', () => ({
@@ -60,6 +65,7 @@ class FakeWebSocket {
 beforeEach(() => {
   wsInstances.length = 0;
   openSpy.mockClear();
+  fitSpy.mockClear();
   fetchSpy.mockReset();
   fetchSpy.mockResolvedValue({
     ok: true,
@@ -127,4 +133,64 @@ describe('XtermSession', () => {
     expect(wsInstances[0]?.url).toBe('ws://x');
     expect(openSpy).toHaveBeenCalled();
   });
+
+  it('refits and sends a resize frame when it becomes visible', async () => {
+    const { rerender } = render(
+      <XtermSession
+        active
+        visible={false}
+        tokenUrl='/api/box/terminal-token'
+        sessionKey='box-1'
+      />,
+    );
+
+    await waitFor(() => expect(wsInstances).toHaveLength(1));
+    const ws = wsInstances[0]!;
+    // Ignore fits/sends from the initial connect; only the visible toggle matters.
+    fitSpy.mockClear();
+    ws.send.mockClear();
+
+    rerender(
+      <XtermSession
+        active
+        visible
+        tokenUrl='/api/box/terminal-token'
+        sessionKey='box-1'
+      />,
+    );
+
+    await waitFor(() => expect(fitSpy).toHaveBeenCalled());
+    await waitFor(() =>
+      expect(ws.send).toHaveBeenCalledWith(
+        expect.stringContaining('"type":"resize"'),
+      ),
+    );
+  });
+
+  it('keeps the WebSocket open when hidden while still active', async () => {
+    const { rerender } = render(
+      <XtermSession
+        active
+        visible
+        tokenUrl='/api/box/terminal-token'
+        sessionKey='box-1'
+      />,
+    );
+
+    await waitFor(() => expect(wsInstances).toHaveLength(1));
+    const ws = wsInstances[0]!;
+
+    rerender(
+      <XtermSession
+        active
+        visible={false}
+        tokenUrl='/api/box/terminal-token'
+        sessionKey='box-1'
+      />,
+    );
+    await Promise.resolve();
+
+    expect(ws.close).not.toHaveBeenCalled();
+    expect(wsInstances).toHaveLength(1);
+  });
 });