Initial support of mutation testing with stryker-js (#3591)

.c8rc.json

@@ -10,8 +10,7 @@
     "src/utilities/typedQueryDocumentNode.ts"
   ],
   "clean": true,
-  "temp-directory": "coverage",
-  "report-dir": "coverage",
+  "report-dir": "reports/coverage",
   "skip-full": true,
   "reporter": ["html", "text"],
   "check-coverage": true,

.eslintignore

@@ -1,8 +1,9 @@
 # Copied from '.gitignore', please keep it in sync.
 /.eslintcache
 /.docusaurus
+/.stryker-tmp
 /node_modules
-/coverage
+/reports
 /npmDist
 /denoDist
 /websiteDist

.github/workflows/mutation-testing.yml

@@ -0,0 +1,32 @@
+name: Mutation Testing
+on:
+  workflow_dispatch:
+  schedule:
+    - cron: '0 0 * * *' # run once every day at 00:00 UTC
+jobs:
+  lint:
+    name: Run mutation testing
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repo
+        uses: actions/checkout@v2
+        with:
+          persist-credentials: false
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v2
+        with:
+          cache: npm
+          node-version-file: '.node-version'
+
+      - name: Install Dependencies
+        run: npm ci --ignore-scripts
+
+      - name: Run mutation testing
+        run: npm run testonly:mutate
+
+      - name: Upload mutation testing report
+        uses: actions/upload-artifact@v2
+        with:
+          name: mutationTestingReport
+          path: ./reports/mutation/mutation.html

.gitignore

@@ -9,8 +9,9 @@
 /.eslintcache
 /.cspellcache
 /.docusaurus
+/.stryker-tmp
 /node_modules
-/coverage
+/reports
 /npmDist
 /denoDist
 /websiteDist

.prettierignore

@@ -2,8 +2,9 @@
 /diff-npm-package.html
 /.eslintcache
 /.docusaurus
+/.stryker-tmp
 /node_modules
-/coverage
+/reports
 /npmDist
 /denoDist
 /websiteDist