Add GitHub Action to Require Tests in Pull Requests (#730)

.github/workflows/require-tests.yml

@@ -0,0 +1,21 @@
+name: 'Require Tests on Code Change'
+
+on:
+  pull_request_target:
+    types: [opened]
+
+jobs:
+  check:
+    name: 'Require Tests on Code Change'
+
+    runs-on: ubuntu-22.04
+
+    steps:
+        - name: "Execute tests-checker-action"
+          uses: infection/[email protected]
+          with:
+            GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+            comment: Could you please add tests to make sure this change works as expected?
+            fileExtensions: '.php'
+            testDir: 'tests'
+            testPattern: '*Test.php'