tests(cluster): add README

Author: abhidg

cluster/README.md

@@ -0,0 +1,43 @@
+# Cluster tests
+
+This folder contains scripts to setup an ephemeral SLURM cluster to test cats
+in a more realistic setting than the current integration tests that use
+macking. The setup builds upon work from upstream
+https://github.com/giovtorres/slurm-docker-cluster with a patched
+[Dockerfile](Dockerfile) that installs the latest release of CATS and makes it
+available in the cluster.
+
+## Setup
+
+Clone this repository (GreenScheduler/cats) and then run
+
+```shell
+./cats/clone.sh
+./cats/build.sh
+```
+to clone the slurm-docker-cluster repo, patch the Dockerfile to install CATS,
+build and start the cluster. Note that this requires `docker` and `docker
+compose` to be present. Currently this compiles a specific SLURM version, so
+this may take a while on older computers. When developing locally, you should
+only need to do this once, unless you update the Dockerfile.
+
+Once the cluster is built and running, then you can run the following to get
+access to the control node:
+
+```shell
+docker exec -it slurmctld bash
+```
+
+For more information about slurm-docker-cluster, consult the upstream
+repository.
+
+## Tests
+
+An automated testing script is supplied which shows programmatic interaction
+with the slurm cluster. Currently cats schedules a short job, and the slurm
+`scontrol` output is checked to see that the job was scheduled correctly. To
+run the test:
+
+```shell
+./cluster/tests.sh
+```