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/BarChartTests.cs

@@ -0,0 +1,51 @@
+using System.Threading.Tasks;
+using Spectre.Console.Testing;
+using Spectre.Verify.Extensions;
+using VerifyXunit;
+using Xunit;
+
+namespace Spectre.Console.Tests.Unit
+{
+    [UsesVerify]
+    [ExpectationPath("Widgets/BarChart")]
+    public sealed class BarChartTests
+    {
+        [Fact]
+        [Expectation("Render")]
+        public async Task Should_Render_Correctly()
+        {
+            // Given
+            var console = new TestConsole();
+
+            // When
+            console.Write(new BarChart()
+                .Width(60)
+                .Label("Number of fruits")
+                .AddItem("Apple", 12)
+                .AddItem("Orange", 54)
+                .AddItem("Banana", 33));
+
+            // Then
+            await Verifier.Verify(console.Output);
+        }
+
+        [Fact]
+        [Expectation("Zero_Value")]
+        public async Task Should_Render_Correctly_2()
+        {
+            // Given
+            var console = new TestConsole();
+
+            // When
+            console.Write(new BarChart()
+                .Width(60)
+                .Label("Number of fruits")
+                .AddItem("Apple", 0)
+                .AddItem("Orange", 54)
+                .AddItem("Banana", 33));
+
+            // Then
+            await Verifier.Verify(console.Output);
+        }
+    }
+}