public void RepositoryLevelHash() {
            var desc = new FileDescriptorEx { FullName = file,UseRepositoryCommit = true};
            GitHelper.Init(dir);
            GitHelper.CommitAll(dir);
            desc.Refresh();
            Assert.AreEqual(desc.Hash,GitHelper.GetCommit(dir).Hash);
            File.WriteAllText(file2,"sample");
            GitHelper.CommitAll(dir);
            Assert.AreNotEqual(desc.Hash, GitHelper.GetCommit(dir).Hash);
            desc.Refresh();
            Assert.AreEqual(desc.Hash, GitHelper.GetCommit(dir).Hash);
	    }
        public void HeaderRepositoryLevelHash()
        {
            File.WriteAllText(file, @"/*!
opts userepositorycommit=true
*/
data");
            var desc = new FileDescriptorEx { FullName = file};
            GitHelper.Init(dir);
            GitHelper.CommitAll(dir);
            desc.Refresh();
            Assert.AreEqual(desc.Hash, GitHelper.GetCommit(dir).Hash);
            File.WriteAllText(file2, "sample");
            GitHelper.CommitAll(dir);
            Assert.AreNotEqual(desc.Hash, GitHelper.GetCommit(dir).Hash);
            desc.Refresh();
            Assert.AreEqual(desc.Hash, GitHelper.GetCommit(dir).Hash);
        }