From 64a9c1fee86251cd09a0b2f253ae14a214f0ae76 Mon Sep 17 00:00:00 2001
From: Anderson Entwistle <46688047+aentwist@users.noreply.github.com>
Date: Tue, 20 Jun 2023 14:42:13 -0400
Subject: [PATCH] docs: note Vue's dependence on system time (#2100)

---
 docs/api/index.md       | 2 ++
 docs/guide/faq/index.md | 9 +++++++++
 2 files changed, 11 insertions(+)

diff --git a/docs/api/index.md b/docs/api/index.md
index 99ac3904c..1e63d406b 100644
--- a/docs/api/index.md
+++ b/docs/api/index.md
@@ -7,6 +7,8 @@ sidebar: auto
 ## mount
 
 Creates a Wrapper that contains the mounted and rendered Vue component to test.
+Note that when mocking dates/timers with Vitest, this must be called after
+`vi.setSystemTime`.
 
 **Signature:**
 
diff --git a/docs/guide/faq/index.md b/docs/guide/faq/index.md
index 1c883cab8..9f89a26b8 100644
--- a/docs/guide/faq/index.md
+++ b/docs/guide/faq/index.md
@@ -2,6 +2,15 @@
 
 [[toc]]
 
+## Mocking Dates and Timers with Vitest
+
+Vue's scheduler depends on the system time. Make sure to mount components
+*after* calling `vi.setSystemTime`, since Vue depends on its side effects.
+Mounting components before calling `vi.setSystemTime` may cause breaks in
+reactivity.
+
+See [vuejs/test-utils#2074](https://github.com/vuejs/test-utils/issues/2074).
+
 ## Vue warn: Failed setting prop
 
 ```