@Test
public void detectsMissingObjectKeys() {

    Node actual = Node.objectNode().withMember("foo", Node.from("bar"));
    Node expected = Node.objectNode().withMember("foo", Node.from("bar")).withMember("fizz", Node.from("buzz"));
    assertThat(NodeDiff.diff(actual, expected),
               contains("[]: Expected key `fizz` not present."));
}