fix(workspace): scroll/diff-race/recovery/editor/mobile polish

apps/next/tests/unit/workspace-helpers.test.ts

@@ -0,0 +1,72 @@
+import { describe, expect, test } from 'vitest';
+
+import {
+  createRequestSequencer,
+  isNearBottom,
+  NEAR_BOTTOM_THRESHOLD,
+  RECOVERY_THRESHOLD,
+  shouldShowRecovery,
+} from '@/components/agent-workspace/workspace-helpers';
+
+describe('createRequestSequencer', () => {
+  test('only the latest issued token is considered current', () => {
+    const sequencer = createRequestSequencer();
+    const first = sequencer.next();
+    const second = sequencer.next();
+
+    // Simulate the first (slower) request resolving after the second: it is
+    // stale and must be dropped.
+    expect(sequencer.isLatest(first)).toBe(false);
+    // The newest request wins.
+    expect(sequencer.isLatest(second)).toBe(true);
+  });
+
+  test('a fresh request supersedes a previously latest one', () => {
+    const sequencer = createRequestSequencer();
+    const token = sequencer.next();
+    expect(sequencer.isLatest(token)).toBe(true);
+    sequencer.next();
+    expect(sequencer.isLatest(token)).toBe(false);
+  });
+});
+
+describe('shouldShowRecovery', () => {
+  test('defaults to a threshold of 3 consecutive failures', () => {
+    expect(RECOVERY_THRESHOLD).toBe(3);
+    expect(shouldShowRecovery(0)).toBe(false);
+    expect(shouldShowRecovery(1)).toBe(false);
+    expect(shouldShowRecovery(2)).toBe(false);
+    expect(shouldShowRecovery(3)).toBe(true);
+    expect(shouldShowRecovery(4)).toBe(true);
+  });
+
+  test('honours a custom threshold', () => {
+    expect(shouldShowRecovery(1, 2)).toBe(false);
+    expect(shouldShowRecovery(2, 2)).toBe(true);
+  });
+});
+
+describe('isNearBottom', () => {
+  test('true when within the threshold band of the bottom', () => {
+    expect(
+      isNearBottom({ scrollHeight: 1000, scrollTop: 940, clientHeight: 100 }),
+    ).toBe(true);
+  });
+
+  test('false when scrolled up beyond the threshold', () => {
+    expect(
+      isNearBottom({ scrollHeight: 1000, scrollTop: 200, clientHeight: 100 }),
+    ).toBe(false);
+  });
+
+  test('uses NEAR_BOTTOM_THRESHOLD as the default band', () => {
+    expect(NEAR_BOTTOM_THRESHOLD).toBe(80);
+    // Exactly at the threshold is not "near" (strict less-than).
+    expect(
+      isNearBottom({ scrollHeight: 1000, scrollTop: 820, clientHeight: 100 }),
+    ).toBe(false);
+    expect(
+      isNearBottom({ scrollHeight: 1000, scrollTop: 821, clientHeight: 100 }),
+    ).toBe(true);
+  });
+});