2 files changed, 32 insertions, 4 deletions
diff --git a/tests/auto/corelib/io/qbuffer/CMakeLists.txt b/tests/auto/corelib/io/qbuffer/CMakeLists.txt
index 661bad7866..87022451a0 100644
--- a/tests/auto/corelib/io/qbuffer/CMakeLists.txt
+++ b/tests/auto/corelib/io/qbuffer/CMakeLists.txt
@@ -1,12 +1,16 @@
 # Copyright (C) 2022 The Qt Company Ltd.
-# SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only WITH Qt-GPL-exception-1.0
-
-# Generated from qbuffer.pro.
+# SPDX-License-Identifier: BSD-3-Clause
 
 #####################################################################
 ## tst_qbuffer Test:
 #####################################################################
 
+if(NOT QT_BUILD_STANDALONE_TESTS AND NOT QT_BUILDING_QT)
+    cmake_minimum_required(VERSION 3.16)
+    project(tst_qbuffer LANGUAGES CXX)
+    find_package(Qt6BuildInternals REQUIRED COMPONENTS STANDALONE_TEST)
+endif()
+
 qt_internal_add_test(tst_qbuffer
     SOURCES
         tst_qbuffer.cpp
diff --git a/tests/auto/corelib/io/qbuffer/tst_qbuffer.cpp b/tests/auto/corelib/io/qbuffer/tst_qbuffer.cpp
index 93e0d6fce8..acfd60e224 100644
--- a/tests/auto/corelib/io/qbuffer/tst_qbuffer.cpp
+++ b/tests/auto/corelib/io/qbuffer/tst_qbuffer.cpp
@@ -1,5 +1,5 @@
 // Copyright (C) 2016 The Qt Company Ltd.
-// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only WITH Qt-GPL-exception-1.0
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only
 
 #include <QTest>
 #include <QTestEventLoop>
@@ -15,6 +15,7 @@ class tst_QBuffer : public QObject
     Q_OBJECT
 private slots:
     void open();
+    void openWriteOnlyDoesNotTruncate();
     void getSetCheck();
     void readBlock();
     void readBlockPastEnd();
@@ -111,6 +112,29 @@ void tst_QBuffer::open()
     b.close();
 }
 
+void tst_QBuffer::openWriteOnlyDoesNotTruncate()
+{
+    QBuffer b;
+    const auto data = QByteArrayLiteral("Hey, presto!");
+
+    {
+        QVERIFY(b.open(QIODevice::WriteOnly));
+        b.write(data);
+        b.close();
+    }
+    {
+        QVERIFY(b.open(QIODevice::ReadOnly));
+        QCOMPARE(b.readAll(), data);
+        b.close();
+    }
+    {
+        QVERIFY(b.open(QIODevice::WriteOnly));
+        QCOMPARE(b.size(), data.size());
+        QCOMPARE(b.pos(), 0);
+        b.close();
+    }
+}
+
 // some status() tests, too
 void tst_QBuffer::readBlock()
 {