java.lang.IllegalStateException: Error launching request

[sm4]

I am running Arquillian 1.1.1.Final + TestNG in managed JBoss 7.1.1.Final. I have two simple test classes, both extend a common test class that extends Arquillian class. When I run them separately, they work just fine. When I run both of them, the one that is executed second, fails in few tests with the following cause:

Caused by: java.lang.IllegalStateException: Error launching request at http://127.0.0.1:14380/test/ArquillianServletRunner?outputMode=serializedObject&className=com.example.SecondEJBTest&methodName=testOne. No result returned
    at org.jboss.arquillian.protocol.servlet.ServletMethodExecutor.executeWithRetry(ServletMethodExecutor.java:139)
    at org.jboss.arquillian.protocol.servlet.ServletMethodExecutor.invoke(ServletMethodExecutor.java:99)
    ... 83 more
  

I also tried restarting the server between the classes by using this in arquillian.xml:

<engine>
  <property name="maxTestClassesBeforeRestart">1</property>
</engine>

But I get the same result.

What "kind of" works is when I force order of the tests by using dependsOnMethod, but I prefer not to, because these two classes are just a tip of an iceberg. It makes me think that maybe there is some problem with parallel execution. However I use this config of my failsafe plugin. I am using failsafe, because there are already unit tests running from surefire, because we use testng suite files that arquillian ignores.

<parallel>none</parallel>
<threadCount>1</threadCount>

Any ideas are greatly appreciated!

[sm4]

Here's a simple example of what fails:

public abstract class ParentTest<T extends MyEntity> extends Arquillian {

  @Test
  public static void testMethodThatDoesNotDependOnAnyone() {
  }

  // bunch of test classes that use the annotation @Test(dependsOnMethods="previousMethod")


  @Test
  public static void testMethodOne() {
  }


  @Test(dependsOnMethods="testMethodOne")
  public static void testMethodTwo() {
  }

  // more methods here

}

public class ChildTestOne extends ParentTest<ExampleOne> {

}


public class ChildTestTwo extends ParentTest<ExampleTwo> {

}

The testMethodThatDoesNotDependOnAnyone will fail in one class (ChildTestOne) with the exception above. If I add testMethodAddedToProveMyPoint() both will fail. In the other class they will run just fine.

Also setting maxTestClassesBeforeRestart to 1 doesn't work properly - both classes will be tested in the second JBoss start.