public void RemoveNodeShouldHaveNoReferencesToTheOriginalTreeNodes()
{
// Arrange
var charNodeA = new CharacterNode('a');
var charNodeB = new CharacterNode('b');
var childNodes = new List <RegexNode> {
charNodeA, charNodeB
};
var target = new TestRegexNode(childNodes);
// Act
RegexNode result = target.RemoveNode(charNodeA);
// Assert
result.ShouldNotBe(target);
result.ChildNodes.ShouldNotContain(charNodeA);
result.ChildNodes.ShouldNotContain(charNodeB);
}