Add simple test for basic. default date properties of DateFieldBackend

Signed-off-by: Claudio Cambra <claudio.cambra@nextcloud.com>

src/gui/filedetails/datefieldbackend.h

@@ -17,6 +17,8 @@
 #include <QDate>
 #include <QObject>
 
+class TestDateFieldBackend;
+
 namespace OCC
 {
 namespace Quick
@@ -78,6 +80,8 @@ signals:
     void validDateChanged();
 
 private:
+    friend class ::TestDateFieldBackend;
+
     QDate _date = QDate::currentDate();
     QDate _minimumDate;
     QDate _maximumDate;
@@ -87,4 +91,4 @@ private:
 };
 
 } // namespace Quick
-} // namespace OCC
+} // namespace OCC

test/testdatefieldbackend.cpp

@@ -22,4 +22,24 @@ using namespace OCC;
 class TestDateFieldBackend : public QObject
 {
     Q_OBJECT
-}
+
+private slots:
+    void testDefaultBehaviour()
+    {
+        constexpr auto dateStringFormat = "dd/MM/yyyy";
+
+        Quick::DateFieldBackend backend;
+        backend._dateFormat = dateStringFormat;
+
+        const auto currentDate = QDate::currentDate();
+        const auto currentDateMSecs = currentDate.startOfDay(Qt::UTC).toMSecsSinceEpoch();
+        const auto currentDateString = currentDate.toString(dateStringFormat);
+
+        QCOMPARE(backend.date(), currentDate);
+        QCOMPARE(backend.dateMsecs(), currentDateMSecs);
+        QCOMPARE(backend.dateString(), currentDateString);
+    }
+};
+
+QTEST_MAIN(TestDateFieldBackend)
+#include "testdatefieldbackend.moc"