private void verifyVersionedSemantics(final ForeignJoinSubscriptionSendNode<?, ?> joinThisNode, final boolean expectedValue) {
        final ProcessorSupplier<?, ?, ?, ?> thisProcessorSupplier = joinThisNode.processorParameters().processorSupplier();
        assertInstanceOf(SubscriptionSendProcessorSupplier.class, thisProcessorSupplier);
        final SubscriptionSendProcessorSupplier<?, ?, ?> joinThis = (SubscriptionSendProcessorSupplier<?, ?, ?>) thisProcessorSupplier;
        assertEquals(expectedValue, joinThis.isUseVersionedSemantics());
    }
The join node has two parents and the graph looks like:
root ---> source (t1)
source ---> map , windowed-4, join
map ---> windowed-3, join
streams/src/test/java/org/apache/kafka/streams/kstream/internals/InternalStreamsBuilderTest.java