diff --git a/tests/e2e/helpers/terminal-pty-write-spy.unit.test.ts b/tests/e2e/helpers/terminal-pty-write-spy.unit.test.ts
index 5c9226080088..a211c7673bcb 100644
--- a/tests/e2e/helpers/terminal-pty-write-spy.unit.test.ts
+++ b/tests/e2e/helpers/terminal-pty-write-spy.unit.test.ts
@@ -1,3 +1,5 @@
+import type { ElectronApplication } from '@stablyai/playwright-test'
+import * as electron from 'electron'
 import { afterEach, expect, it, vi } from 'vitest'
 import { setTerminalPtyWriteDelay } from './terminal-pty-write-spy'
 
@@ -5,14 +7,21 @@ afterEach(() => vi.unstubAllGlobals())
 
 it('sets and clears paste backpressure using the main-process evaluate argument', async () => {
   vi.stubGlobal('__terminalPtyWriteDelayMs', 0)
-  const evaluate = vi.fn()
-  evaluate.mockImplementation(
-    (callback: (electron: object, argument: number) => void, delay: number) => callback({}, delay)
-  )
+  const evaluate = vi.fn<ElectronApplication['evaluate']>()
+  evaluate.mockImplementation(async (callback, delay) => {
+    if (typeof callback !== 'function') {
+      throw new Error('Expected a main-process evaluate callback')
+    }
+    return callback(electron, delay)
+  })
   const app = { evaluate }
 
+  if (!('__terminalPtyWriteDelayMs' in globalThis)) {
+    throw new Error('Expected the stubbed PTY write delay')
+  }
+
   await setTerminalPtyWriteDelay(app, 35)
-  expect(Reflect.get(globalThis, '__terminalPtyWriteDelayMs')).toBe(35)
+  expect(globalThis.__terminalPtyWriteDelayMs).toBe(35)
   await setTerminalPtyWriteDelay(app, 0)
-  expect(Reflect.get(globalThis, '__terminalPtyWriteDelayMs')).toBe(0)
+  expect(globalThis.__terminalPtyWriteDelayMs).toBe(0)
 })