I have created a dll project. This one build without errors.
I want to test this dll so I create a QtTest class.
But when I try to build the unit test .pro I get the following errors :

tst_testsconnection.obj : error LNK2001: symbole externe non résolu "public: virtual void * __cdecl QSerialPort::`scalar deleting destructor'(unsigned int)" (??_GQSerialPort@@UEAAPEAXI@Z)
tst_testsconnection.obj : error LNK2001: symbole externe non résolu "public: virtual void * __cdecl QSerialPort::`vector deleting destructor'(unsigned int)" (??_EQSerialPort@@UEAAPEAXI@Z)

In my Dll I have a class who uses QSerialPort. But I have no issue on how to fix this link error.
If I remove the QOBJECT macro and the signals/slot part there is no more any link errors.
My dll project was created using QtCreator wizard.

Below the .h of my class in the dll :

#ifndef RS232UNIWHEEL_H
#define RS232UNIWHEEL_H

#include "connectionlibrary_global.h"

#include <QObject>
#include <QtSerialPort/QSerialPort>

class CONNECTIONLIBRARYSHARED_EXPORT RS232UniWheel : public QObject
{
    Q_OBJECT

public:
    RS232UniWheel();
    ~RS232UniWheel();
    void open();
    bool isOpen();
    void close();
    void writeList();
    void writeStart();
    void writeStop();
    QByteArray readAll();
    QString getError();

signals:
    void errorOccurred(QSerialPort::SerialPortError error);
    void readyRead();

public slots:
    void readData();
    void handleError(QSerialPort::SerialPortError error);

private :
    QSerialPort m_serial;

};

#endif // RS232UNIWHEEL_H

All these are quite simple usage of Qt code.

If anyone has an idea ??

Thanks.