Check that /blob/ URLs can be opened

Also check that changing from a valid repository/blob URL to an invalid
URL causes the Clone/Open buttons to become inactive.

Author: jcansdale

test/GitHub.App.UnitTests/ViewModels/Dialog/Clone/RepositorySelectViewModelTests.cs

@@ -57,6 +57,8 @@ public async Task Filter(string filter, string owner, string name, string url, i
         [TestCase("filter", null)]
         [TestCase("https://github.com", null)]
         [TestCase("https://github.com/github/VisualStudio", "https://github.com/github/VisualStudio")]
+        [TestCase("https://github.com/github/VisualStudio/blob/master/README.md", "https://github.com/github/VisualStudio/blob/master/README.md")]
+        [TestCase("https://github.com/github/VisualStudio/pull/2208", null)]
         public void Set_Repository_When_Filter_Is_Url(string url, string expectUrl)
         {
             var expectCloneUrl = expectUrl != null ? new UriString(expectUrl) : null;
@@ -69,6 +71,24 @@ public void Set_Repository_When_Filter_Is_Url(string url, string expectUrl)
 
             Assert.That(target.Repository?.CloneUrl, Is.EqualTo(expectCloneUrl));
         }
+
+        [TestCase("filter;https://github.com/github/VisualStudio", "https://github.com/github/VisualStudio")]
+        [TestCase("https://github.com/github/VisualStudio;filter", null)]
+        public void Change_Filters(string filters, string expectUrl)
+        {
+            var expectCloneUrl = expectUrl != null ? new UriString(expectUrl) : null;
+            var repositoryCloneService = CreateRepositoryCloneService();
+            var gitHubContextService = new GitHubContextService(Substitute.For<IGitHubServiceProvider>(),
+                Substitute.For<IGitService>(), Substitute.For<IVSServices>());
+            var target = new RepositorySelectViewModel(repositoryCloneService, gitHubContextService);
+
+            foreach (var filter in filters.Split(';'))
+            {
+                target.Filter = filter;
+            }
+
+            Assert.That(target.Repository?.CloneUrl, Is.EqualTo(expectCloneUrl));
+        }
     }
 
     static IGitHubContextService CreateGitHubContextService()