add some info on running tests

Author: joshuanianji

README.md

@@ -20,6 +20,7 @@ Idris Versions: `v0.5.1`, `v0.6.0`, `v0.7.0`, `latest` (Up to date with [Idris2/
   - [Running Locally](#running-locally)
     - [Build Latest](#build-latest)
     - [Build From a Tagged Release/SHA commit](#build-from-a-tagged-releasesha-commit)
+    - [Running tests](#running-tests)
   - [Credit](#credit)
 
 ## Motivation
@@ -86,9 +87,13 @@ To run the images locally, I recommend opening the workspace in the Devcontainer
 This is the default behaviour when running the script.
 
 ```bash
+# this is the only module we need, so i chose not to create a requirements.txt file
+pip install -U requests
+
 # builds base from latest commit on the Idris repo. Tag is base-latest
 python scripts/build-image.py --image base
-python scripts/build-image.py --image devcontainer --tag devcontainer-latest-test
+python scripts/build-image.py --image ubuntu
+python scripts/build-image.py --image devcontainer --tag devcontainer-latest
 ```
 
 ### Build From a Tagged Release/SHA commit
@@ -99,6 +104,26 @@ python scripts/build-image.py --image base --sha 58e5d156621cfdd4c54df26abf7ac96
 python scripts/build-image.py --image devcontainer --version v0.6.0
 ```
 
+### Running tests
+
+We have some tests to ensure the docker images are working as expected, using [bats](https://github.com/bats-core/bats-core). The bats CLI tool should already be installed in the devcontainer.
+
+You'll need to install the `bats-support` and `bats-assert` libraries. I found the easiest way to do this was to clone via git:
+
+```bash
+git clone https://github.com/bats-core/bats-support test/test_helper/bats-support
+git clone https://github.com/bats-core/bats-assert test/test_helper/bats-assert
+```
+
+To run a test on a specific image, set the required variables, and run the bats command:
+
+```bash
+export LIB_PATH=$(pwd)/tests/test_helper
+export DOCKER_IMAGE=
+export IDRIS_VERSION=latest
+bats tests/base.bats
+```
+
 ## Credit
 
 * [dgellow/idris-docker-image](https://github.com/dgellow/idris-docker-image) for giving me a starting point