Moved analyzer tests to its own project

Also moves tests to `./test` which makes it possible
for all test projects to share the same .editorconfig
files and similar.

test/Spectre.Console.Tests/Unit/AnsiConsoleTests.Advanced.cs

@@ -0,0 +1,61 @@
+using Shouldly;
+using Spectre.Console.Advanced;
+using Spectre.Console.Testing;
+using Xunit;
+
+namespace Spectre.Console.Tests.Unit
+{
+    public sealed partial class AnsiConsoleTests
+    {
+        public sealed class Advanced
+        {
+            [Fact]
+            public void Should_Write_Ansi_Codes_To_Console_If_Supported()
+            {
+                // Given
+                var console = new TestConsole()
+                    .SupportsAnsi(true)
+                    .Colors(ColorSystem.Standard)
+                    .EmitAnsiSequences();
+
+                // When
+                console.WriteAnsi("Hello");
+
+                // Then
+                console.Output.NormalizeLineEndings()
+                    .ShouldBe("Hello");
+            }
+
+            [Fact]
+            public void Should_Not_Write_Ansi_Codes_To_Console_If_Not_Supported()
+            {
+                // Given
+                var console = new TestConsole()
+                    .SupportsAnsi(false)
+                    .Colors(ColorSystem.Standard)
+                    .EmitAnsiSequences();
+
+                // When
+                console.WriteAnsi("Hello");
+
+                // Then
+                console.Output.NormalizeLineEndings()
+                    .ShouldBeEmpty();
+            }
+
+            [Fact]
+            public void Should_Return_Ansi_For_Renderable()
+            {
+                // Given
+                var console = new TestConsole().Colors(ColorSystem.TrueColor);
+                var markup = new Console.Markup("[yellow]Hello [blue]World[/]![/]");
+
+                // When
+                var result = console.ToAnsi(markup);
+
+                // Then
+                result.ShouldBe("Hello World!");
+            }
+        }
+    }
+}