Add dot group element (#43)

Sources/DotNetGraph.Tests/Core/DotGroupTests.cs

@@ -0,0 +1,41 @@
+using System.IO;
+using System.Threading.Tasks;
+using DotNetGraph.Compilation;
+using DotNetGraph.Core;
+using DotNetGraph.Extensions;
+using FluentAssertions;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+namespace DotNetGraph.Tests.Core;
+
+[TestClass]
+public class DotGroupTests
+{
+    [TestMethod]
+    public async Task EmptyGroupElements()
+    {
+        var group = new DotGroup();
+
+        await using var writer = new StringWriter();
+        var context = new CompilationContext(writer, new CompilationOptions());
+        await group.CompileAsync(context);
+
+        var result = writer.GetStringBuilder().ToString();
+        result.Should().Be("{\n}\n");
+    }
+    [TestMethod]
+    public async Task GroupElementsAndAttributes()
+    {
+        var group = new DotGroup().WithAttribute("rank", "same");
+        group.Add(new DotNode().WithIdentifier("node-1"));
+        group.Add(new DotNode().WithIdentifier("node-2"));
+
+
+        await using var writer = new StringWriter();
+        var context = new CompilationContext(writer, new CompilationOptions());
+        await group.CompileAsync(context);
+
+        var result = writer.GetStringBuilder().ToString();
+        result.Should().Be("{\n\t\"rank\"=same\n\t\"node-1\"\n\t\"node-2\"\n}\n");
+    }
+}

Sources/DotNetGraph/Core/DotGroup.cs

@@ -0,0 +1,21 @@
+using System.Threading.Tasks;
+using DotNetGraph.Compilation;
+
+namespace DotNetGraph.Core
+{
+    public class DotGroup : DotBaseGraph
+    {
+        public override async Task CompileAsync(CompilationContext context)
+        {
+            await context.WriteIndentationAsync();
+            await context.WriteLineAsync("{");
+            ++context.IndentationLevel;
+            await CompileAttributesAsync(context);
+            foreach (var element in Elements)
+                await element.CompileAsync(context);
+            --context.IndentationLevel;
+            await context.WriteIndentationAsync();
+            await context.WriteLineAsync("}");
+        }
+    }
+}