Add initial graph implementation

Contributes to #68

src/Html2Markdown/ContentNodeList.cs

@@ -0,0 +1,20 @@
+using System;
+using AngleSharp.Dom;
+
+namespace Html2Markdown
+{
+	public class ContentNodeList
+	{
+		private INodeList _childNodes;
+
+		public ContentNodeList(INodeList childNodes)
+		{
+			this._childNodes = childNodes;
+		}
+
+		public int Size()
+		{
+			return _childNodes.Length;
+		}
+	}
+}

src/Html2Markdown/HtmlGraph.cs

@@ -0,0 +1,25 @@
+using AngleSharp.Dom.Html;
+using AngleSharp.Parser.Html;
+
+namespace Html2Markdown {
+	public class HtmlGraph : IContentGraph
+	{
+		private IHtmlDocument _document;
+
+		public HtmlGraph(string html)
+		{
+			var parser = new HtmlParser();
+			this._document = parser.Parse(html);
+
+			if (HasChildren()) {
+				ChildNodes = new ContentNodeList(_document.Body.ChildNodes);
+			}
+		}
+
+		public ContentNodeList ChildNodes { get; private set; }
+		public bool HasChildren()
+		{
+			return _document.Body.HasChildNodes;
+		}
+	}
+}

src/Html2Markdown/IContentGraph.cs

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+namespace Html2Markdown {
+	public interface IContentGraph
+	{
+		ContentNodeList ChildNodes { get; }
+
+		bool HasChildren();
+	}
+}

test/Html2Markdown.Test/HtmlContentGraphTest.cs

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+using System;
+using NUnit.Framework;
+
+namespace Html2Markdown {
+
+	[TestFixture]
+	public class HtmlContentGraphTest
+	{
+		[Test]
+		public void HtmlContentGraph_ImplementsIContentGraph() {
+			var graph = CreateGraph("");
+
+			Assert.That(graph, Is.InstanceOf<IContentGraph>());
+		}
+
+		[Test]
+		public void HasChildren_WhenHtmlLoadedThatHasChildren_ThenShouldReturnTrue() {
+			const string html = @"<p>some content</p>";
+			var graph = CreateGraph(html);
+
+			Assert.That(graph.HasChildren(), Is.True);
+		}
+
+		[Test]
+		public void ChildNodes_WhenHtmlLoadedHasChildren_ThenShouldReturnNodes() {
+			const string html = @"<p>some content</p>";
+			var graph = CreateGraph(html);
+
+			Assert.That(graph.ChildNodes, Is.InstanceOf<ContentNodeList>());
+		}
+
+		[Test]
+		public void ChildNodes_WhenHtmlLoadedHasOneChild_ThenChildNodesSizeShouldBeOne() {
+			const string html = @"<p>some content</p>";
+			var graph = CreateGraph(html);
+
+			Assert.That(graph.ChildNodes.Size(), Is.EqualTo(1));
+		}
+
+		[Test]
+		public void ChildNodes_WhenHtmlLoadedHasTwoChild_ThenChildNodesSizeShouldBeTwo() {
+			const string html = @"<p>some content</p><p>some more content</p>";
+			var graph = CreateGraph(html);
+
+			Assert.That(graph.ChildNodes.Size(), Is.EqualTo(2));
+		}
+
+		private IContentGraph CreateGraph(string html)
+		{
+			return new HtmlGraph(html);
+		}
+	}
+}