public void CanRestoreFile(){
var githelper = new GitHelper{DirectoryName = dirname,AuthorName =Applications.Application.Current.Principal.CurrentUser.Identity.Name};
githelper.Connect();
var initial = githelper.GetCommitId();
var currentFile = githelper.GetContent("x");
Assert.Null(currentFile);
githelper.WriteAndCommit("x","a","is a");
var first = githelper.GetCommitId();
Assert.AreNotEqual(initial,first);
githelper.WriteAndCommit("x", "b", "is b");
var second = githelper.GetCommitId();
Assert.AreNotEqual(initial, second);
var content = githelper.ReadFile("x");
Assert.AreEqual("b",content);
githelper.RestoreSingleFile("x",first);
content = githelper.ReadFile("x");
Assert.AreEqual("a",content);
}
