4 files changed, 103 insertions, 0 deletions
diff --git a/tests/manual/corelib/time/CMakeLists.txt b/tests/manual/corelib/time/CMakeLists.txt
new file mode 100644
index 0000000000..b8e6aa2f18
--- /dev/null
+++ b/tests/manual/corelib/time/CMakeLists.txt
@@ -0,0 +1,4 @@
+# Copyright (C) 2023 The Qt Company Ltd.
+# SPDX-License-Identifier: BSD-3-Clause
+
+add_subdirectory(zonechange)
diff --git a/tests/manual/corelib/time/foreachzone b/tests/manual/corelib/time/foreachzone
new file mode 100755
index 0000000000..480679885a
--- /dev/null
+++ b/tests/manual/corelib/time/foreachzone
@@ -0,0 +1,30 @@
+#!/bin/sh
+# Usage: foreachzone command [args...]
+#
+# The command is run with eval, so can include embedded shell
+# metacharacters such as | and ||. It is run in a sub-shell, so can
+# change environment or cd to a different directory without
+# complicating later runs of the same command.
+#
+# It is run repeatedly, with the TZ environment variable set to each
+# timezone name in turn, excluding the copies of zoneinfo/ under its
+# posix/ and right/ sub-dirs. Symbolic links are included (as long as
+# they point to valid zone data).
+#
+# For example, in the top level of a build tree,
+#   foreachzone ninja tst_qdate_check
+# will run all the QDate tests in every time zone (this may take some
+# time).
+
+DIR=/usr/share/zoneinfo
+[ -d "$DIR" ] || DIR=/usr/lib/zoneinfo
+
+find $DIR -type d \( -name posix -o -name right \) -prune -o \( -type f -o -type l \) -print \
+    | while read f
+do
+    # To filter out symlinks in zoneinfo/ itself, uncomment this line:
+    # echo "$f" | grep -wq 'zoneinfo/.*/' || [ ! -h "$f" ] || continue
+    # To skip all symlinks, omit the -L here:
+    file -L "$f" | grep -wq 'timezone data .*, version' || continue
+    ( export TZ=${f#*/zoneinfo/}; eval "$@" )
+done
diff --git a/tests/manual/corelib/time/zonechange/CMakeLists.txt b/tests/manual/corelib/time/zonechange/CMakeLists.txt
new file mode 100644
index 0000000000..474779849f
--- /dev/null
+++ b/tests/manual/corelib/time/zonechange/CMakeLists.txt
@@ -0,0 +1,9 @@
+# Copyright (C) 2023 The Qt Company Ltd.
+# SPDX-License-Identifier: BSD-3-Clause
+
+qt_internal_add_manual_test(zonechange
+    SOURCES
+        tst_zonechange.cpp
+    LIBRARIES
+        Qt::Core
+)
diff --git a/tests/manual/corelib/time/zonechange/tst_zonechange.cpp b/tests/manual/corelib/time/zonechange/tst_zonechange.cpp
new file mode 100644
index 0000000000..5ca33f1396
--- /dev/null
+++ b/tests/manual/corelib/time/zonechange/tst_zonechange.cpp
@@ -0,0 +1,60 @@
+// Copyright (C) 2023 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only
+
+#include <QtCore/qcoreapplication.h>
+
+#include <QtCore/qdatetime.h>
+#if QT_CONFIG(timezone)
+#include <QtCore/qtimezone.h>
+#endif
+
+#include <chrono>
+#include <thread>
+
+using namespace std::chrono;
+
+bool distinct(const QDateTime &left, const QDateTime &right)
+{
+    if (left == right)
+        return false;
+
+    qInfo() << "  Actual:" << left << "\nExpected:" << right;
+    return true;
+}
+
+// Exit status: 0 success, 1 test failed, 2 test not viable.
+int main(int argc, char **argv)
+{
+    // Other things may need this indirectly, so make sure it exists:
+    QCoreApplication ignored(argc, argv);
+    if (!qEnvironmentVariableIsEmpty("TZ")) {
+        qInfo("Environment variable TZ over-rides system setting; you need to clear it.");
+        return 2;
+    }
+
+    QDateTime date = QDateTime(QDate(2020, 2, 20), QTime(20, 20, 20));
+    QDateTime copy = date;
+    if (distinct(date, copy))
+        return 1;
+#if QT_CONFIG(timezone)
+    const auto prior = QTimeZone::systemTimeZoneId();
+#endif
+
+    qInfo("You have two minutes in which to change the system time-zone setting.");
+    std::this_thread::sleep_for(120s);
+#if QT_CONFIG(timezone)
+    if (QTimeZone::systemTimeZoneId() == prior) {
+        qInfo("Too slow.");
+        return 2;
+    }
+#endif
+
+    if (distinct(copy, date))
+        return 1;
+    QDateTime copy2 = copy.addMSecs(2);
+    QDateTime date2 = date.addMSecs(2);
+    if (distinct(copy2, date2))
+        return 1;
+
+    return 0;
+}