Migrate tests to XUnit

AdventOfCode2017.Tests/Day02_Tests.cs

@@ -1,11 +1,10 @@
-using Microsoft.VisualStudio.TestTools.UnitTesting;
+using Xunit;
 
 namespace AdventOfCode2017.Tests
 {
-    [TestClass]
     public class Day02_Tests
     {
-        [TestMethod]
+        [Fact]
         public void ResolvePart1__Test()
         {
             Day02 day02 = new Day02();
@@ -16,10 +15,10 @@ namespace AdventOfCode2017.Tests
                 "2 4 6 8",
             });
 
-            Assert.AreEqual("18", result);
+            Assert.Equal("18", result);
         }
 
-        [TestMethod]
+        [Fact]
         public void ResolvePart2__Test()
         {
             Day02 day02 = new Day02();
@@ -30,7 +29,7 @@ namespace AdventOfCode2017.Tests
                 "3 8 6 5",
             });
 
-            Assert.AreEqual("9", result);
+            Assert.Equal("9", result);
         }
     }
 }