I'm running Gitolite over the Git repository and I have post-receive hook there written in Python. I need to execute "git" command at git repository directory. There are few lines of code:

proc = subprocess.Popen(['git', 'log', '-n1'], cwd='/home/git/repos/testing.git' stdout=subprocess.PIPE, stderr=subprocess.PIPE)
proc.communicate()

After I make new commit and push to repository, scripts executes and says

fatal: Not a git repository: '.'

If I run

proc = subprocess.Popen(['pwd'], cwd='/home/git/repos/testing.git' stdout=subprocess.PIPE, stderr=subprocess.PIPE)

it says, as expected, correct path to git repository (/home/git/repos/testing.git)

If I run this script manually from bash, it works correct and show correct output of "git log". What I'm doing wrong?