first step
Fix pretty simple tests
Throw docker_registry.exceptions in case of wrong configuration passed
Fix configuration drive in groups* tests
I was too lazy to check it
Catch proper exception while subdir is being removed. Add test for removing inexistent path
Cover border cases in s_write and s_remove related with IO errors
Fix test again
copy implementation of gen_random_string into my own test case
Replace IOError raising with exceptions.UnspecifiedError
Fix test according to new exceptions
Merge pull request #11 from noxiouz/raise_coverage_up

Raise coverage up