This little location provider for geoclue can be used to fake location. It provides location set in gsettings to GeoClue.
autoreconf -i
./configure
make install
glib-compile-schemas /usr/share/glib-2.0/schemas
gsettings set fi.inz.GeoclueMock latitude 12.34
gsettings set fi.inz.GeoclueMock longitude 43.21
gsettings set fi.inz.GeoclueMock fuzz 0.01
gesttings set fi.inz.GeoclueMock active true
Then launch your favourite app that uses geoclue and it should get the faked position.