2 files changed, 11 insertions, 3 deletions
diff --git a/src/testlib/qtestcase.cpp b/src/testlib/qtestcase.cpp
index b1e6401b0f..c08ad58d75 100644
--- a/src/testlib/qtestcase.cpp
+++ b/src/testlib/qtestcase.cpp
@@ -285,6 +285,14 @@ namespace QTestPrivate
 
 namespace QTest
 {
+
+QString Internal::formatTryTimeoutDebugMessage(q_no_char8_t::QUtf8StringView expr, int timeout, int actual)
+{
+    return QLatin1String("QTestLib: This test case check (\"%1\") failed because the requested timeout (%2 ms) was too short, %3 ms would have been sufficient this time.")
+            // ### Qt 7: remove the toString() (or earlier, when arg() can handle QUtf8StringView), passing the view directly
+            .arg(expr.toString(), QString::number(timeout), QString::number(actual));
+}
+
 extern Q_TESTLIB_EXPORT int lastMouseTimestamp;
 
 class WatchDog;
diff --git a/src/testlib/qtestcase.h b/src/testlib/qtestcase.h
index b046232c65..25385b327a 100644
--- a/src/testlib/qtestcase.h
+++ b/src/testlib/qtestcase.h
@@ -143,9 +143,7 @@ do {\
     if (!(expr)) { \
         QTRY_LOOP_IMPL((expr), (2 * timeoutValue), step);\
         if (expr) { \
-            QString msg = QString::fromUtf8("QTestLib: This test case check (\"%1\") failed because the requested timeout (%2 ms) was too short, %3 ms would have been sufficient this time."); \
-            msg = msg.arg(QString::fromUtf8(#expr)).arg(timeoutValue).arg(timeoutValue + qt_test_i); \
-            QFAIL(qPrintable(msg)); \
+            QFAIL(qPrintable(QTest::Internal::formatTryTimeoutDebugMessage(u8"" #expr, timeoutValue, timeoutValue + qt_test_i))); \
         } \
     }
 
@@ -239,6 +237,8 @@ namespace QTest
 {
     namespace Internal {
 
+    Q_TESTLIB_EXPORT QString formatTryTimeoutDebugMessage(q_no_char8_t::QUtf8StringView expr, int timeout, int actual);
+
     template<typename T> // Output registered enums
     inline typename std::enable_if<QtPrivate::IsQEnumHelper<T>::Value, char*>::type toString(T e)
     {