Add QTZ::displayName() benchmarks

Task-number: QTBUG-115158
Pick-to: 6.7 6.5 6.2 5.15
Change-Id: I7465a19f6003cfae7507d798fadeab22bf1b118d
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
(cherry picked from commit 01acb888e0f9f06cac07d69d8c934eac9d32daf3)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

tests/benchmarks/corelib/time/qtimezone/tst_bench_qtimezone.cpp

@@ -20,6 +20,8 @@ private Q_SLOTS:
     void systemTimeZone();
     void zoneByName_data();
     void zoneByName();
+    void displayName_data();
+    void displayName();
     void transitionList_data();
     void transitionList();
     void transitionsForward_data() { transitionList_data(); }
@@ -89,6 +91,72 @@ void tst_QTimeZone::zoneByName()
     Q_UNUSED(zone);
 }
 
+void tst_QTimeZone::displayName_data()
+{
+    QTest::addColumn<QByteArray>("ianaId");
+    QTest::addColumn<QDateTime>("when");
+    QTest::addColumn<QLocale>("where");
+    QTest::addColumn<QTimeZone::NameType>("type");
+
+    const QLocale sys = QLocale::system();
+    const QLocale locs[] = {
+        QLocale::c(),
+        // System locale and its CLDR-equivalent:
+        sys, QLocale(sys.language(), sys.script(), sys.territory()),
+        // An assortment of CLDR ones:
+        QLocale(QLocale::Arabic, QLocale::Lebanon),
+        QLocale(QLocale::Chinese, QLocale::China),
+        QLocale(QLocale::English, QLocale::UnitedStates),
+        QLocale(QLocale::French, QLocale::France),
+        QLocale(QLocale::Finnish, QLocale::Finland),
+        QLocale(QLocale::German, QLocale::Germany),
+        QLocale(QLocale::NorwegianBokmal, QLocale::Norway),
+        QLocale(QLocale::Ukrainian, QLocale::Ukraine),
+    };
+    const QByteArray locName[] = { "C", "system", "CLDR-sys" };
+    const QDateTime times[] = {
+        QDate(1970, 1, 1).startOfDay(QTimeZone::UTC),
+        QDate(2000, 2, 29).startOfDay(QTimeZone::UTC),
+        QDate(2020, 4, 30).startOfDay(QTimeZone::UTC),
+    };
+
+    const auto names = enoughZones();
+    for (const auto &name : names) {
+        for (const auto &when : times) {
+            qsizetype locIndex = 0;
+            for (const auto &where : locs) {
+                const QByteArray dt = when.toString(Qt::ISODate).toUtf8();
+                const QByteArray loc =
+                    locIndex < std::size(locName) ? locName[locIndex] : where.bcp47Name().toUtf8();
+                QTest::addRow("%s@%s/%s:default", name.data(), dt.data(), loc.data())
+                    << name << when << where << QTimeZone::DefaultName;
+                QTest::addRow("%s@%s/%s:long", name.data(), dt.data(), loc.data())
+                    << name << when << where << QTimeZone::LongName;
+                QTest::addRow("%s@%s/%s:short", name.data(), dt.data(), loc.data())
+                    << name << when << where << QTimeZone::ShortName;
+                QTest::addRow("%s@%s/%s:offset", name.data(), dt.data(), loc.data())
+                    << name << when << where << QTimeZone::OffsetName;
+                ++locIndex;
+            }
+        }
+    }
+}
+
+void tst_QTimeZone::displayName()
+{
+    QFETCH(const QByteArray, ianaId);
+    QFETCH(const QDateTime, when);
+    QFETCH(const QLocale, where);
+    QFETCH(const QTimeZone::NameType, type);
+
+    const QTimeZone zone(ianaId);
+    QString name;
+    QBENCHMARK {
+        name = zone.displayName(when, type, where);
+    }
+    Q_UNUSED(name);
+}
+
 void tst_QTimeZone::transitionList_data()
 {
     QTest::addColumn<QByteArray>("name");