From 5175bec268fb902c54e3e606d38cdcd1582dafc9 Mon Sep 17 00:00:00 2001
From: James Titcumb <james@asgrim.com>
Date: Wed, 18 Mar 2026 12:57:26 +0000
Subject: [PATCH] Add mutation testing with Infection

---
 .github/workflows/continuous-integration.yml | 16 ++++++++++++++++
 infection.json5                              | 11 +++++++++++
 2 files changed, 27 insertions(+)
 create mode 100644 infection.json5

diff --git a/.github/workflows/continuous-integration.yml b/.github/workflows/continuous-integration.yml
index 2c610d3..54ffeaa 100644
--- a/.github/workflows/continuous-integration.yml
+++ b/.github/workflows/continuous-integration.yml
@@ -203,6 +203,22 @@ jobs:
       - name: Run phpstan
         run: vendor/bin/phpstan
 
+  mutation-testing:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Setup PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: 8.4
+          extensions: intl, sodium, zip
+          tools: infection
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+      - uses: actions/checkout@v6
+      - uses: ramsey/composer-install@v3
+      - name: Run infection
+        run: sudo infection --min-msi=68 --min-covered-msi=68 --threads=4 --show-mutations=max --no-progress
+
   build-assets:
     needs:
       - unit-tests
diff --git a/infection.json5 b/infection.json5
new file mode 100644
index 0000000..c963786
--- /dev/null
+++ b/infection.json5
@@ -0,0 +1,11 @@
+{
+    "$schema": "https://raw.githubusercontent.com/infection/infection/0.32.6/resources/schema.json",
+    "source": {
+        "directories": [
+            "src"
+        ]
+    },
+    "mutators": {
+        "@default": true
+    }
+}
\ No newline at end of file