Enforcing code standards in git before commit is accepted

Question

Alright, here's the scenario: A team of developers wants to ensure all new code matches the defined coding standards and all the unit tests are passing before a commit is accepted. Here's the trick, all of the tests need to run on a dedicated testing machine and we do not have access to modify the git server so this must be done using a local commit hook on each dev machine.

While the specs are pretty strict (we're not switching to windows or subversion, for example) this is a real world problem so there is some flexibility if you have a solution that almost fits.

• We're using Git and *nix.
• The updated code needs to be sent to another server to run the test suite.
• A list of modified files needs to be provided to ensure they match the coding standard.
• Its a rather large codebase, so we should send the smallest amount of information necessary to ensure identical copies of the codebase.
• If the tests fail a message needs to be displayed with the error and the commit should be blocked.
• Assume we trust our dev team and its okay to allow the tests to be bypassed with --no-verify option.

The question: What is the best way to get the test server to sync up with the local environment to run the tests? Some sort of hash-to-hash matching with a git patch for the new commit? Skip Git altogether and just do an rsync? Something else altogether?

Update 8/7/13: I shot myself in the foot by even mentioning the remote repo. The point isn't to block the code from being pushed to the shared / remote repo, its to prevent the local commit from even happening. Whether or not this would be considered a best practice is not really the point in this case, as this is specific to a small team of developers who all want this exact functionality. The question is about the best way to achieve the goal.

Answer 1

Add a custom git command which:

1. Temporarily does the commit
2. Pushes it to the remote server
3. Runs the tests (using a CI server, post-receive hook, or ssh)
4. Reverts the commit if the tests fail

Create an executable called git-test-n-commit and place it in your path:

#!/bin/bash
echo "Committing results..."
git commit "$@"
echo "Pushing to remote testing server..."
git push remote-server-git-url remote-branch -f
echo "Running tests"
ssh remote-server 'cd my_repo; run-my-tests' || 
   (echo "Tests failed, undoing commit" && git reset HEAD^)

Then instead of calling git commit ARGS, the developers can call git test-n-commit ARGS. If the tests pass the code will remain committed. If the tests fail it will be as if it was never committed.