@Test
public void managersEqualReturnsFalseWhenOneNull() {

    // given
    var node = new HierarchyTreeNode(userMock);
    var otherNode = new HierarchyTreeNode(otherUserMock);
    otherNode.manager = node;
    // when / then
    assertThat(node.managersEqual(otherNode)).isFalse();
}