In my environment the StateProviderTest .test2() fails sometimes (about 10% of the time) with the following error(s):

Tests run: 4233, Failures: 1, Errors: 0, Skipped: 0, Time elapsed: 428.06 sec <<< FAILURE!
test2(org.infinispan.statetransfer.StateProviderTest)  Time elapsed: 0.042 sec  <<< FAILURE!
java.lang.AssertionError
	at org.junit.Assert.fail(Assert.java:92)
	at org.junit.Assert.assertTrue(Assert.java:43)
	at org.junit.Assert.assertTrue(Assert.java:54)
	at org.infinispan.statetransfer.StateProviderTest.test2(StateProviderTest.java:316)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)

The reason why is that test2() feeds the StateProvider a ThreadPoolExecutorService to execute a OutboundTransfer task asynchronously and right after forcing a state transfer
asserts that there is a StateTransfer in progress. Sometimes the executor service manages to execute the task and as a result it clear the ‘transfersByDestination’ map, and thus the test cannot assert that the state transfer is happening

OTOH, the method test1() never fails because it users a mock executor service which never executes the task, so the state transfer map will always contain the outbound task after initiating the state transfer and thus always visible from outside

The quick fix is to also use a mock executor test for the test2()