Make ERA SSBv3 issuing/departure day accessors const

src/lib/era/ssbv3ticket.cpp

@@ -54,7 +54,7 @@ bool SSBv3Ticket::maybeSSB(const QByteArray& data)
     return (data.at(0) >> 4) == SSB_VERSION;
 }
 
-QDate SSBv3Ticket::issueDate(const QDateTime &contextDate)
+QDate SSBv3Ticket::issueDate(const QDateTime &contextDate) const
 {
     if (m_data.isEmpty() || ticketTypeCode() > SSBv3Ticket::RPT) {
         return {};
@@ -69,7 +69,7 @@ QDate SSBv3Ticket::issueDate(const QDateTime &contextDate)
     return d;
 }
 
-QDate SSBv3Ticket::type1DepartureDay(const QDateTime& contextDate)
+QDate SSBv3Ticket::type1DepartureDay(const QDateTime& contextDate) const
 {
     if (ticketTypeCode() != SSBv3Ticket::IRT_RES_BOA) {
         return {};

src/lib/era/ssbv3ticket.h

@@ -112,9 +112,9 @@ public:
     bool isValid() const;
 
     /** Date of issue. */
-    Q_INVOKABLE QDate issueDate(const QDateTime &contextDate = QDateTime::currentDateTime());
+    Q_INVOKABLE QDate issueDate(const QDateTime &contextDate = QDateTime::currentDateTime()) const;
     /** Departure day for type 1 (IRT/RES/BOA) tickets. */
-    Q_INVOKABLE QDate type1DepartureDay(const QDateTime &contextDate = QDateTime::currentDateTime());
+    Q_INVOKABLE QDate type1DepartureDay(const QDateTime &contextDate = QDateTime::currentDateTime()) const;
 
     /** Raw barcode data. */
     QByteArray rawData() const;