Make sure to use C locale during time tests that assume it

Some format and parse tests for time and date-time depended on locale
but had test data for the C locale (so fail if the test-environment
has, e.g., LANG=de_DE@utf8).  So impose the C locale (until Qt 6).

The date-time test did *some* attempts at fixing for locale, but
failed to handle am/pm; and we do have "### Qt 6" comments in
Q(Date|Time)+::fromString indicating that we intend to switch these
methods to use the C locale by default (which shall fix this once and
for all).  So rip out the incomplete localization now and test we work
properly at least when the locale used *is* C.  Add a comment to the
matching QDate test to rip out its (presently adequate) matching code
once we do get to Qt 6 and make fromString() use the C locale.

QDateTimeParser uses systemLocale(), which is initialized the first
time it gets accessed; so we need to frob the locale *early*; doing so
in the test-class constructor is about as early as we conveniently
can; and seems to work (while doing it in individual tests does not).
(There is no point rolling back at the end; the QSystemLocale global
has been set up by then, so the roll-back would merely leave the
global out of sync with setlocale() and the environment.)

Task-number: QTBUG-58728
Change-Id: Ifa6778a80276050a099387a6dab15a1096be7561
Reviewed-by: Marc Mutz <marc.mutz@kdab.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/tests/auto/corelib/tools/qdate/tst_qdate.cpp b/tests/auto/corelib/tools/qdate/tst_qdate.cpp
index 0e189ba7aa..f88eac1a9f 100644
--- a/tests/auto/corelib/tools/qdate/tst_qdate.cpp
+++ b/tests/auto/corelib/tools/qdate/tst_qdate.cpp
@@ -1033,7 +1033,8 @@ void tst_QDate::fromStringFormat_data()
     QTest::addColumn<QString>("format");
     QTest::addColumn<QDate>("expected");
 
-    //get localized names
+    // Undo this (inline the C-locale versions) for ### Qt 6
+    // Get localized names:
     QString january = QDate::longMonthName(1);
     QString february = QDate::longMonthName(2);
     QString march = QDate::longMonthName(3);