chore(qa/engine-it): add test for required transaction isolation level

related to #CAM-6203

qa/integration-tests-engine/src/test/java/org/camunda/bpm/integrationtest/functional/transactions/TransactionIsolationLevelTest.java

@@ -0,0 +1,45 @@
+package org.camunda.bpm.integrationtest.functional.transactions;
+
+import org.apache.ibatis.session.SqlSession;
+import org.apache.ibatis.session.TransactionIsolationLevel;
+import org.camunda.bpm.engine.ProcessEngine;
+import org.camunda.bpm.engine.impl.cfg.ProcessEngineConfigurationImpl;
+import org.camunda.bpm.integrationtest.util.AbstractFoxPlatformIntegrationTest;
+import org.jboss.arquillian.container.test.api.Deployment;
+import org.jboss.arquillian.junit.Arquillian;
+import org.jboss.shrinkwrap.api.spec.WebArchive;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import javax.inject.Inject;
+import java.sql.SQLException;
+
+import static org.junit.Assert.assertEquals;
+
+
+@RunWith(Arquillian.class)
+public class TransactionIsolationLevelTest extends AbstractFoxPlatformIntegrationTest {
+
+  @Deployment
+  public static WebArchive processArchive() {
+    return initWebArchiveDeployment();
+  }
+
+  @Inject
+  private ProcessEngine processEngine;
+
+  @Test
+  public void testTransactionIsolationLevelOnConnection() {
+    ProcessEngineConfigurationImpl processEngineConfiguration = (ProcessEngineConfigurationImpl) processEngine.getProcessEngineConfiguration();
+    SqlSession sqlSession = processEngineConfiguration.getDbSqlSessionFactory()
+        .getSqlSessionFactory()
+        .openSession();
+    try {
+      int transactionIsolation = sqlSession.getConnection().getTransactionIsolation();
+      assertEquals("TransactionIsolationLevel for connection is " + transactionIsolation + " instead of " + TransactionIsolationLevel.READ_COMMITTED,
+          TransactionIsolationLevel.READ_COMMITTED.getLevel(), transactionIsolation);
+    } catch (SQLException e) {
+      e.printStackTrace();
+    }
+  }
+}