chore: refactoring and tests (#12629)

packages/app/src/context/layout-scroll.test.ts

@@ -1,36 +1,44 @@
-import { describe, expect, test } from "bun:test"
+import { describe, expect, test, vi } from "bun:test"
 import { createScrollPersistence } from "./layout-scroll"
 
 describe("createScrollPersistence", () => {
-  test("debounces persisted scroll writes", async () => {
-    const snapshot = {
-      session: {
-        review: { x: 0, y: 0 },
-      },
-    } as Record<string, Record<string, { x: number; y: number }>>
-    const writes: Array<Record<string, { x: number; y: number }>> = []
-    const scroll = createScrollPersistence({
-      debounceMs: 10,
-      getSnapshot: (sessionKey) => snapshot[sessionKey],
-      onFlush: (sessionKey, next) => {
-        snapshot[sessionKey] = next
-        writes.push(next)
-      },
-    })
+  test("debounces persisted scroll writes", () => {
+    vi.useFakeTimers()
+    try {
+      const snapshot = {
+        session: {
+          review: { x: 0, y: 0 },
+        },
+      } as Record<string, Record<string, { x: number; y: number }>>
+      const writes: Array<Record<string, { x: number; y: number }>> = []
+      const scroll = createScrollPersistence({
+        debounceMs: 10,
+        getSnapshot: (sessionKey) => snapshot[sessionKey],
+        onFlush: (sessionKey, next) => {
+          snapshot[sessionKey] = next
+          writes.push(next)
+        },
+      })
 
-    for (const i of Array.from({ length: 30 }, (_, n) => n + 1)) {
-      scroll.setScroll("session", "review", { x: 0, y: i })
+      for (const i of Array.from({ length: 30 }, (_, n) => n + 1)) {
+        scroll.setScroll("session", "review", { x: 0, y: i })
+      }
+
+      vi.advanceTimersByTime(9)
+      expect(writes).toHaveLength(0)
+
+      vi.advanceTimersByTime(1)
+
+      expect(writes).toHaveLength(1)
+      expect(writes[0]?.review).toEqual({ x: 0, y: 30 })
+
+      scroll.setScroll("session", "review", { x: 0, y: 30 })
+      vi.advanceTimersByTime(20)
+
+      expect(writes).toHaveLength(1)
+      scroll.dispose()
+    } finally {
+      vi.useRealTimers()
     }
-
-    await new Promise((resolve) => setTimeout(resolve, 40))
-
-    expect(writes).toHaveLength(1)
-    expect(writes[0]?.review).toEqual({ x: 0, y: 30 })
-
-    scroll.setScroll("session", "review", { x: 0, y: 30 })
-    await new Promise((resolve) => setTimeout(resolve, 20))
-
-    expect(writes).toHaveLength(1)
-    scroll.dispose()
   })
 })