node.writeTo(output);
BytesStreamInput input = new BytesStreamInput(output.bytes());
MergeNode node2 = new MergeNode();
node2.readFrom(input);
assertThat(node.numUpstreams(), is(node2.numUpstreams()));
assertThat(node.executionNodes(), is(node2.executionNodes()));
assertThat(node.contextId(), is(node2.contextId()));
assertThat(node.inputTypes(), is(node2.inputTypes()));