tst_QLocale: check negative/positiveSign() is never == u'\0'

Code in QTextStream assumes this, so we need to make sure it holds for
all locales.

The test is modelled after testNames(), which is from 2012, so should
be available in all active branches, incl. 5.15 ESM.

Task-number: QTBUG-138475
Pick-to: 6.10 6.9 6.8 6.5 5.15
Change-Id: Ib1552bb0e75a35676e1fd2b3901784654dd76998
Reviewed-by: Edward Welbourne <[email protected]>

1 files changed, 16 insertions, 0 deletions

diff --git a/tests/auto/corelib/text/qlocale/tst_qlocale.cpp b/tests/auto/corelib/text/qlocale/tst_qlocale.cpp
index bfc6074689b..50e17728cf3 100644
--- a/tests/auto/corelib/text/qlocale/tst_qlocale.cpp
+++ b/tests/auto/corelib/text/qlocale/tst_qlocale.cpp
@@ -78,6 +78,9 @@ private slots:
     void negativeZero_data();
     void negativeZero();
 
+    void signsNeverCompareEqualToNullCharacter_data() { testNames_data(); }
+    void signsNeverCompareEqualToNullCharacter();
+
     void dayOfWeek();
     void dayOfWeek_data();
     void formatDate();
@@ -2114,6 +2117,19 @@ void tst_QLocale::negativeZero()
     QCOMPARE(locale.toString(std::copysign(0.0, -1.0)), expect);
 }
 
+void tst_QLocale::signsNeverCompareEqualToNullCharacter() // otherwise QTextStream has a problem
+{
+    QFETCH(QLocale::Language, language);
+    QFETCH(const QLocale::Territory, country);
+
+    if (language == QLocale::AnyLanguage && country == QLocale::AnyTerritory)
+        language = QLocale::C;
+
+    const QLocale loc(language, country);
+    QCOMPARE_NE(loc.negativeSign(), QChar());
+    QCOMPARE_NE(loc.positiveSign(), QChar());
+}
+
 void tst_QLocale::dayOfWeek_data()
 {
     QTest::addColumn<QDate>("date");