MockNode.cs

public class MockNode
{
    private readonly IDictionary<string, object> properties;

    public MockNode()
    {
        this.properties = new Dictionary<string, object>();
    }

    public MockNode AddProperty(string alias, string value)
    {
        properties.Add(alias, value);
        return this;
    }

    public INode Mock()
    {
        var node = Substitute.For<INode>();
        foreach (var pair in properties)
        {
            var property = Substitute.For<IProperty>();
            property.Alias.Returns(pair.Key);
            property.Value.Returns(pair.Value);
            node.GetProperty(pair.Key).Returns(property);
        }

        return node;
    }
}

MockNodeFactory.cs

public class MockNodeFactory
{
    public static INode BuildNode(IDictionary<string, object> properties)
    {
        var node = Substitute.For<INode>();
        foreach (var pair in properties)
        {
            var property = Substitute.For<IProperty>();
            property.Alias.Returns(pair.Key);
            property.Value.Returns(pair.Value);
            node.GetProperty(pair.Key).Returns(property);   
        }

        return node;
    }
}

MockNodeUsage.cs

var mockNode = new MockNode()
    .AddProperty("Body", "Body")
    .AddProperty("Title", "Title")
    .Mock();