Refactor: extract data_size() in T_ChunkDetector test
Refactor: extract data_size() in T_ChunkDetector test

alhowaidi/cvmfsNDN,Gangbiao/cvmfs,trshaffer/cvmfs,alhowaidi/cvmfsNDN,djw8605/cvmfs,DrDaveD/cvmfs,Moliholy/cvmfs,DrDaveD/cvmfs,Gangbiao/cvmfs,DrDaveD/cvmfs,reneme/cvmfs,reneme/cvmfs,DrDaveD/cvmfs,Moliholy/cvmfs,cvmfs/cvmfs,djw8605/cvmfs,alhowaidi/cvmfsNDN,djw8605/cvmfs,alhowaidi/cvmfsNDN,cvmfs/cvmfs,cvmfs/cvmfs,cvmfs/cvmfs,reneme/cvmfs,cvmfs/cvmfs,Gangbiao/cvmfs,Gangbiao/cvmfs,Moliholy/cvmfs,djw8605/cvmfs,trshaffer/cvmfs,trshaffer/cvmfs,Moliholy/cvmfs,trshaffer/cvmfs,trshaffer/cvmfs,DrDaveD/cvmfs,reneme/cvmfs,alhowaidi/cvmfsNDN,Moliholy/cvmfs,cvmfs/cvmfs,DrDaveD/cvmfs,cvmfs/cvmfs,DrDaveD/cvmfs,Gangbiao/cvmfs,reneme/cvmfs,djw8605/cvmfs