[nosetests] Improved CSVWriter test cases

[znorm][nosetests] Fixed ZNorm tests with the new scorewriter
2 jobs for scorewriter in 5 minutes and 57 seconds (queued for 1 second)
Status Job ID Name Coverage
  Build
passed #220369
docker
build_linux_37

00:05:54

83.0%
passed #220368
macosx
build_macosx_37

00:05:56

83.0%