document docker tests

README.md

@@ -169,22 +169,21 @@ heroku config:set BUILDPACK_URL=<your-github-url>#your-branch
 
 ## Testing
 
-[Anvil](https://github.com/ddollar/anvil) is a generic build server for Heroku.
+The buildpack tests use [Docker](https://www.docker.com/) to simulate
+Heroku's Cedar and Cedar-14 containers.
 
-```
-gem install anvil-cli
-```
-
-The [heroku-anvil CLI plugin](https://github.com/ddollar/heroku-anvil) is a wrapper for anvil.
+To run the test suite:
 
 ```
-heroku plugins:install https://github.com/ddollar/heroku-anvil
+test/docker
 ```
 
-The [ddollar/test](https://github.com/ddollar/buildpack-test) buildpack runs `bin/test` on your app/buildpack.
+Or to just test in cedar or cedar-14:
 
 ```
-heroku build -b ddollar/test # -b can also point to a local directory
+test/docker cedar
+test/docker cedar-14
 ```
 
-For more info on testing, see [Best Practices for Testing Buildpacks](https://discussion.heroku.com/t/best-practices-for-testing-buildpacks/294) on the Heroku discussion forum.
+The tests are run via the vendored [shunit2](http://shunit2.googlecode.com/svn/trunk/source/2.1/doc/shunit2.html)
+test framework.

test/docker

@@ -1,7 +1,21 @@
 #!/usr/bin/env bash
 
-echo "Running tests in docker (cedar-14)..."
-docker run -v $(pwd):/buildpack:ro --rm -it heroku/cedar:14 bash -c 'cp -r /buildpack /buildpack_test; cd /buildpack_test/; test/run;'
-echo ""
-echo "Running tests in docker (cedar)..."
-docker run -v $(pwd):/buildpack:ro --rm -it fabiokung/cedar bash -c 'cp -r /buildpack /buildpack_test; cd /buildpack_test/; test/run;'
+cedar-14() {
+  echo "Running tests in docker (cedar-14)..."
+  docker run -v $(pwd):/buildpack:ro --rm -it heroku/cedar:14 bash -c 'cp -r /buildpack /buildpack_test; cd /buildpack_test/; test/run;'
+  echo ""
+}
+
+cedar() {
+  echo "Running tests in docker (cedar)..."
+  docker run -v $(pwd):/buildpack:ro --rm -it fabiokung/cedar bash -c 'cp -r /buildpack /buildpack_test; cd /buildpack_test/; test/run;'
+}
+
+if [ "$1" == "cedar-14" ]; then
+  cedar-14
+elif [ "$1" == "cedar" ]; then
+  cedar
+else
+  cedar-14
+  cedar
+fi