public void ImmutableNode_replaces_child_in_clone_current_instance()
{
// ARRANGE
var child = new ImmutableNode <string, int>("a");
var node = new ImmutableNode <string, int>().AddChild(child);
node.SetValue(1);
var secondChild = new ImmutableNode <string, int>("a");
// ACT
var result = node.ReplaceChild(child, secondChild);
// ASSERT
Assert.NotSame(node, result);
Assert.True(node.HasChildNodes);
Assert.True(result.HasChildNodes);
Assert.Equal(1, result.Value);
var(found, readChildNode) = node.TryGetChildNode("a");
Assert.True(found);
Assert.Same(child, readChildNode);
(found, readChildNode) = result.TryGetChildNode("a");
Assert.True(found);
Assert.Same(secondChild, readChildNode);
}
public void ImmutableNode_removes_child_from_clone_of_current_instance()
{
// ARRANGE
var child = new ImmutableNode <string, int>("a");
var node = new ImmutableNode <string, int>(null, 1).AddChild(child);
// ACT
var result = node.RemoveChild(child);
// ASSERT
Assert.NotSame(node, result);
Assert.True(node.HasChildNodes);
Assert.False(result.HasChildNodes);
Assert.Equal(1, result.Value);
var(found, readChild) = node.TryGetChildNode("a");
Assert.True(found);
Assert.Same(child, readChild);
(found, readChild) = result.TryGetChildNode("a");
Assert.False(found);
}
public void ImmutableNode_adds_child_to_clone_of_current_instance()
{
// ARRANGE
var child = new ImmutableNode <string, int>("a");
var node = new ImmutableNode <string, int>();
node.SetValue(1);
// ACT
var result = node.AddChild(child);
// ASSERT
// node creates a clone with the new child.
Assert.NotSame(node, result);
Assert.False(node.HasChildNodes);
Assert.True(result.HasChildNodes);
Assert.True(result.HasValue);
Assert.Equal(1, result.Value);
Assert.Same(child, result.ChildNodes.Single());
var(found, addedChild) = node.TryGetChildNode("a");
Assert.False(found);
(found, addedChild) = result.TryGetChildNode("a");
Assert.True(found);
Assert.Same(child, addedChild);
}
public void ImmutableNode_fails_on_replacing_unknown_child()
{
// ARRANGE
var child = new ImmutableNode <string, int>("a");
var node = new ImmutableNode <string, int>(null).AddChild(child);
var secondChild = new ImmutableNode <string, int>("b");
// ACT
var result = Assert.Throws <InvalidOperationException>(() => node.ReplaceChild(child, secondChild));
// ASSERT
Assert.Equal("Key of child to replace (key='a') and new child (key='b') must be equal", result.Message);
Assert.True(node.HasChildNodes);
Assert.Same(child, node.ChildNodes.Single());
var(found, addedChild) = node.TryGetChildNode("a");
Assert.True(found);
Assert.Same(child, addedChild);
}