From 065c316effd6ccba539c47035857469205c714b1 Mon Sep 17 00:00:00 2001
From: eps1lon <silbermann.sebastian@gmail.com>
Date: Sat, 8 Oct 2022 13:54:40 +0200
Subject: [PATCH] fix: Prevent "missing act" warning for in-flight promises

---
 src/pure.js | 29 ++++++++++++++++++++++++++++-
 1 file changed, 28 insertions(+), 1 deletion(-)

diff --git a/src/pure.js b/src/pure.js
index 94b3b2bd..af90a273 100644
--- a/src/pure.js
+++ b/src/pure.js
@@ -12,6 +12,19 @@ import act, {
 } from './act-compat'
 import {fireEvent} from './fire-event'
 
+function jestFakeTimersAreEnabled() {
+  /* istanbul ignore else */
+  if (typeof jest !== 'undefined' && jest !== null) {
+    return (
+      // legacy timers
+      setTimeout._isMockFunction === true || // modern timers
+      Object.prototype.hasOwnProperty.call(setTimeout, 'clock')
+    )
+  } // istanbul ignore next
+
+  return false
+}
+
 configureDTL({
   unstable_advanceTimersWrapper: cb => {
     return act(cb)
@@ -23,7 +36,21 @@ configureDTL({
     const previousActEnvironment = getIsReactActEnvironment()
     setReactActEnvironment(false)
     try {
-      return await cb()
+      const result = await cb()
+      // Drain microtask queue.
+      // Otherwise we'll restore the previous act() environment, before we resolve the `waitFor` call.
+      // The caller would have no chance to wrap the in-flight Promises in `act()`
+      await new Promise(resolve => {
+        setTimeout(() => {
+          resolve()
+        }, 0)
+
+        if (jestFakeTimersAreEnabled()) {
+          jest.advanceTimersByTime(0)
+        }
+      })
+
+      return result
     } finally {
       setReactActEnvironment(previousActEnvironment)
     }