From 8d993e8045752b6162471333174317cc40e0961f Mon Sep 17 00:00:00 2001
From: Jonathan Grynspan <jgrynspan@apple.com>
Date: Mon, 26 Jun 2023 18:17:58 -0400
Subject: [PATCH] Merge pull request #4787 from
 apple/jgrynspan/test_readToEndOfFileAndNotify-concurrency-bug

Fix a concurrency bug in the TestFileHandle.test_readToEndOfFileAndNotify() unit test.
---
 Tests/Foundation/Tests/TestFileHandle.swift | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/Tests/Foundation/Tests/TestFileHandle.swift b/Tests/Foundation/Tests/TestFileHandle.swift
index 09879e4572..67618ea858 100644
--- a/Tests/Foundation/Tests/TestFileHandle.swift
+++ b/Tests/Foundation/Tests/TestFileHandle.swift
@@ -481,8 +481,7 @@ class TestFileHandle : XCTestCase {
     
     func test_readToEndOfFileAndNotify() {
         let handle = createFileHandle()
-        var readSomeData = false
-        
+        let readSomeData = XCTestExpectation(description: "At least some data must've been read")
         let done = expectation(forNotification: FileHandle.readCompletionNotification, object: handle, notificationCenter: .default) { (notification) -> Bool in
             guard let data = notification.userInfo?[NSFileHandleNotificationDataItem] as? Data else {
                 XCTFail("Couldn't find the data in the user info: \(notification)")
@@ -490,7 +489,7 @@ class TestFileHandle : XCTestCase {
             }
             
             if !data.isEmpty {
-                readSomeData = true
+                readSomeData.fulfill()
                 handle.readInBackgroundAndNotify()
                 return false
             } else {
@@ -500,8 +499,7 @@ class TestFileHandle : XCTestCase {
         
         handle.readInBackgroundAndNotify()
         
-        wait(for: [done], timeout: 10)
-        XCTAssertTrue(readSomeData, "At least some data must've been read")
+        wait(for: [readSomeData, done], timeout: 10)
     }
     
     func test_readToEndOfFileAndNotify_readError() {