private void verifyVersionedSemantics(final TableFilterNode<?, ?> filterNode, final boolean expectedValue) {
        final ProcessorSupplier<?, ?, ?, ?> processorSupplier = filterNode.processorParameters().processorSupplier();
        assertInstanceOf(KTableFilter.class, processorSupplier);
        final KTableFilter<?, ?> tableFilter = (KTableFilter<?, ?>) processorSupplier;
        assertEquals(expectedValue, tableFilter.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