Add new dependnecy and test for UTF-8 BOM fix in views

src/Microsoft.AspNetCore.Diagnostics.Elm/project.json

@@ -43,6 +43,7 @@
     },
     "netstandard1.3": {
       "dependencies": {
+        "System.Text.Encoding.Extensions": "4.0.11-*",
         "System.Threading": "4.0.11-*"
       }
     }

src/Microsoft.AspNetCore.Diagnostics.EntityFrameworkCore/project.json

@@ -44,6 +44,7 @@
     },
     "netstandard1.3": {
       "dependencies": {
+        "System.Text.Encoding.Extensions": "4.0.11-*",
         "System.Threading": "4.0.11-*"
       }
     }

test/Microsoft.AspNetCore.Diagnostics.FunctionalTests/WelcomePageSampleTest.cs

@@ -20,13 +20,14 @@ namespace Microsoft.AspNetCore.Diagnostics.FunctionalTests
         [Fact]
         public async Task WelcomePage_ShowsWelcome()
         {
-            // Arrange
             var request = new HttpRequestMessage(HttpMethod.Get, "http://localhost/");
 
-            // Act
             var response = await Client.SendAsync(request);
 
-            // Assert
+            var bytes = await response.Content.ReadAsByteArrayAsync();
+            Assert.True(bytes.Length > 1);
+            Assert.NotEqual(0xEF, bytes[0]); // No leading UTF-8 BOM
+
             var body = await response.Content.ReadAsStringAsync();
             Assert.Equal(HttpStatusCode.OK, response.StatusCode);
             Assert.Contains("Your ASP.NET Core application has been successfully started", body);