@Test
public void returnsMembers() {

    StructureShape shape = StructureShape.builder()
            .id("ns.foo#bar")
            .addMember("foo", ShapeId.from("ns.foo#bam"))
            .addMember("baz", ShapeId.from("ns.foo#bam"))
            .build();
    assertThat(shape.members(), hasSize(2));
    // Members are ordered.
    assertThat(shape.members(), contains(shape.getMember("foo").get(), shape.getMember("baz").get()));
    assertThat(shape.getAllMembers().keySet(), contains("foo", "baz"));
}