Tests related to invalid repository now pass.

libgit2sharp.Tests/WhenOpeningARepository.cs

@@ -10,21 +10,17 @@ public class InstanciatingARepository
         const string PathToRepository = "../../Resources/testrepo.git";
 
         [Test]
-        [Ignore("https://github.com/libgit2/libgit2/issues/issue/28")]
         public void ShouldThrowIfPassedANonValidGitDirectory()
         {
             var notAValidRepo = Path.GetTempPath();
-            var exception = Assert.Throws<Exception>(() => new Repository(notAValidRepo));
-            Assert.Fail("To be finalized.");
+            Assert.Throws<NotAValidRepositoryException>(() => new Repository(notAValidRepo));
         }
 
         [Test]
-        [Ignore("https://github.com/libgit2/libgit2/issues/issue/28")]
         public void ShouldThrowIfPassedANonExistingFolder()
         {
             var notAValidRepo = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, Guid.NewGuid().ToString());
-            var exception = Assert.Throws<Exception>(() => new Repository(notAValidRepo));
-            Assert.Fail("To be finalized.");
+            Assert.Throws<NotAValidRepositoryException>(() => new Repository(notAValidRepo));
         }
 
         [Test]

libgit2sharp/NotAValidRepositoryException.cs

+using System;
+
+namespace libgit2sharp
+{
+    public class NotAValidRepositoryException : Exception
+    {
+    }
+}
\ No newline at end of file

libgit2sharp/Repository.cs

@@ -62,14 +62,23 @@ private void OpenRepository(Func<OperationResult> opener)
         {
             OperationResult result = opener();
 
-            if (result != OperationResult.GIT_SUCCESS)
+            if (result == OperationResult.GIT_SUCCESS)
             {
-                _repositoryPtr = IntPtr.Zero;
-                throw new Exception(Enum.GetName(typeof(OperationResult), result));
+                _resolver = new ObjectResolver(_repositoryPtr, this);
+                _details = BuildRepositoryDetails(_repositoryPtr);
+                return;
             }
 
-            _resolver = new ObjectResolver(_repositoryPtr, this);
-            _details = BuildRepositoryDetails(_repositoryPtr);
+            _repositoryPtr = IntPtr.Zero;
+
+            switch (result)
+            {
+                case OperationResult.GIT_ENOTAREPO:
+                    throw new NotAValidRepositoryException();
+
+                default:
+                    throw new Exception(Enum.GetName(typeof(OperationResult), result));
+            }
         }
 
         public Header ReadHeader(string objectId)

libgit2sharp/libgit2sharp.csproj

@@ -46,6 +46,7 @@
     <Compile Include="GitDate.cs" />
     <Compile Include="IObjectHeaderReader.cs" />
     <Compile Include="IResolver.cs" />
+    <Compile Include="NotAValidRepositoryException.cs" />
     <Compile Include="ObjectId.cs" />
     <Compile Include="ObjectResolver.cs" />
     <Compile Include="Signature.cs" />