Tests workflow

Author: szhatchenko

.github/workflows/run_tests_on_push_java_8.yaml

@@ -24,5 +24,12 @@ jobs:
         distribution: 'adopt'
         java-version: '8'
 
+    - name: Pre-install xmltest
+      run: |
+        git clone https://github.com/DevelopmentOnTheEdge/xmltest.git
+        && cd xmltest
+        && mvn install -DskipTests=true -Dmaven.javadoc.skip=true -B -V
+        && cd ../
+
     - name: Run tests
       run: mvn -B clean test