update ci

.github/workflows/ci.yml

@@ -44,6 +44,7 @@ jobs:
         phpize
         ./configure
         make
+        make test
 
   php-linux-x64:
     runs-on: ubuntu-latest
@@ -71,6 +72,9 @@ jobs:
       with:
         submodules: recursive
 
+    - name: Install ancient PHPUnit
+      run: composer require --dev --ignore-platform-reqs phpunit/phpunit "4.8.36"
+
     - name: Install dependencies
       run: composer update --no-interaction