Fix scripts/test and add to note about pre-commit hook to contributing

CONTRIBUTING.md

@@ -30,6 +30,17 @@ that should get you started.
    `docker-compose` from anywhere on your machine, it will run your development
    version of Compose.
 
+## Install pre-commit hooks
+
+This step is optional, but recommended. Pre-commit hooks will run style checks
+and in some cases fix style issues for you, when you commit code.
+
+Install the git pre-commit hooks using [tox](https://tox.readthedocs.org) by
+running `tox -e pre-commit` or by following the
+[pre-commit install guide](http://pre-commit.com/#install).
+
+To run the style checks at any time run `tox -e pre-commit`.
+
 ## Submitting a pull request
 
 See Docker's [basic contribution workflow](https://docs.docker.com/project/make-a-contribution/#the-basic-contribution-workflow) for a guide on how to submit a pull request for code or documentation.

script/ci

@@ -10,6 +10,7 @@ set -e
 
 export DOCKER_VERSIONS=all
 export DOCKER_DAEMON_ARGS="--storage-driver=overlay"
+GIT_VOLUME="--volumes-from=$(hostname)"
 . script/test-versions
 
 >&2 echo "Building Linux binary"

script/test

@@ -6,15 +6,10 @@ set -ex
 TAG="docker-compose:$(git rev-parse --short HEAD)"
 
 rm -rf coverage-html
+# Create the host directory so it's owned by $USER
+mkdir -p coverage-html
 
 docker build -t "$TAG" .
-docker run \
-  --rm \
-  --volume="/var/run/docker.sock:/var/run/docker.sock" \
-  -e DOCKER_VERSIONS \
-  -e "TAG=$TAG" \
-  -e "affinity:image==$TAG" \
-  -e "COVERAGE_DIR=$(pwd)/coverage-html" \
-  --entrypoint="script/test-versions" \
-  "$TAG" \
-  "$@"
+
+GIT_VOLUME="--volume=$(pwd)/.git:/code/.git"
+. script/test-versions

script/test-versions

@@ -5,7 +5,10 @@
 set -e
 
 >&2 echo "Running lint checks"
-tox -e pre-commit
+docker run --rm \
+  ${GIT_VOLUME} \
+  --entrypoint="tox" \
+  "$TAG" -e pre-commit
 
 if [ "$DOCKER_VERSIONS" == "" ]; then
   DOCKER_VERSIONS="default"