error while building unittests

[Lakshman]

Can anyone help me fix this error. Faced it while compiling unittests
on ubuntu 14.04.

[ 28%] Built target TestProfile_automoc
Linking CXX executable TestProfile
libsubsurface_corelib.a(qthelper.cpp.o): In function
`parseGpsText(QString const&, double*, double*)':
qthelper.cpp:(.text+0xda8): undefined reference to `MainWindow::instance()'
qthelper.cpp:(.text+0xdb0): undefined reference to `MainWindow::information()'
qthelper.cpp:(.text+0xdca): undefined reference to
`MainTab::trHemisphere(char const*)'
qthelper.cpp:(.text+0xdf4): undefined reference to `MainWindow::instance()'
qthelper.cpp:(.text+0xdfc): undefined reference to `MainWindow::information()'
qthelper.cpp:(.text+0xe16): undefined reference to
`MainTab::trHemisphere(char const*)'
qthelper.cpp:(.text+0xe44): undefined reference to `MainWindow::instance()'
qthelper.cpp:(.text+0xe4c): undefined reference to `MainWindow::information()'
qthelper.cpp:(.text+0xe66): undefined reference to
`MainTab::trHemisphere(char const*)'
qthelper.cpp:(.text+0xe94): undefined reference to `MainWindow::instance()'
qthelper.cpp:(.text+0xe9c): undefined reference to `MainWindow::information()'
qthelper.cpp:(.text+0xeb6): undefined reference to
`MainTab::trHemisphere(char const*)'
collect2: error: ld returned 1 exit status
make[2]: *** [TestProfile] Error 1
make[1]: *** [CMakeFiles/TestProfile.dir/all] Error 2
make: *** [all] Error 2

Thank you,
Lakshman