@Test
  public void testMultipleManagersInSameProcess() throws Exception {
    doTestMultipleManagersInSameProcessWithGroups("red, blue");
  }
This test creates a locator with a colocated membership manager and then creates a second
manager that joins the system of the first.

It then makes assertions about the state of the membership view, closes one of the managers and
makes more assertions. It also ensures that a cache message can be sent from one manager to the
other.
geode-core/src/integrationTest/java/org/apache/geode/distributed/internal/membership/MembershipJUnitTest.java