Add separate project for tests

csharpcore/GuildedRose/ApprovalTest.cs

@@ -1,26 +0,0 @@
-using Xunit;
-using System;
-using System.IO;
-using System.Text;
-using ApprovalTests;
-using ApprovalTests.Reporters;
-
-namespace GuildedRose
-{
-    [UseReporter(typeof(DiffReporter))]
-    public class ApprovalTest
-    {
-        [Fact]
-        public void ThirtyDays()
-        {
-            var fakeoutput = new StringBuilder();
-            Console.SetOut(new StringWriter(fakeoutput));
-            Console.SetIn(new StringReader("a\n"));
-
-            Program.Main(new string[] { });
-            var output = fakeoutput.ToString();
-
-            Approvals.Verify(output);
-        }
-    }
-}

csharpcore/GuildedRose/GildedRoseTest.cs

@@ -1,17 +0,0 @@
-using Xunit;
-using System.Collections.Generic;
-
-namespace GuildedRose
-{
-    public class GildedRoseTest
-    {
-        [Fact]
-        public void foo()
-        {
-            IList<Item> Items = new List<Item> { new Item { Name = "foo", SellIn = 0, Quality = 0 } };
-            GildedRose app = new GildedRose(Items);
-            app.UpdateQuality();
-            Assert.Equal("fixme", Items[0].Name);
-        }
-    }
-}

csharpcore/GuildedRose/GuildedRose.csproj

@@ -6,10 +6,4 @@
     <StartupObject>GuildedRose.Program</StartupObject>
   </PropertyGroup>
 
-  <ItemGroup>
-    <PackageReference Include="ApprovalTests" Version="5.5.0" />
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.10.0" />
-    <PackageReference Include="xunit" Version="2.4.1" />
-    <PackageReference Include="xunit.runner.visualstudio" Version="2.4.3" />
-  </ItemGroup>
 </Project>