From 88a6855255916eb3734c4b5b86f978708530d07f Mon Sep 17 00:00:00 2001
From: Kyle McCormick <kyle@axim.org>
Date: Wed, 5 Jun 2024 08:26:04 -0400
Subject: [PATCH] test: cancel old unit tests when a new PR commit is pushed
 (#34909)

Based on:
* https://docs.github.com/en/actions/using-jobs/using-concurrency#example-using-concurrency-and-the-default-behavior
* https://stackoverflow.com/questions/68418857/how-to-cancel-existing-runs-when-a-new-push-happens-on-github-actions-but-only
---
 .github/workflows/unit-tests.yml | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/.github/workflows/unit-tests.yml b/.github/workflows/unit-tests.yml
index 6f13d2b9aac9..c6513baa0fbb 100644
--- a/.github/workflows/unit-tests.yml
+++ b/.github/workflows/unit-tests.yml
@@ -6,6 +6,12 @@ on:
     branches:
       - master
 
+concurrency:
+  # We only need to be running tests for the latest commit on each PR
+  # (however, we fully test every commit on master, even as new ones land).
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: ${{ github.ref != 'refs/heads/master' }}
+
 jobs:
   run-tests:
     name: ${{ matrix.shard_name }}(py=${{ matrix.python-version }},dj=${{ matrix.django-version }},mongo=${{ matrix.mongo-version }})