Since the release of Windows Identity Foundation, Microsoft always provided us with a development STS that was easy to setup and configure.
However with the release of Visual Studio 2013, the development STS(provided through the Identity and Access Control extension) is gone. A good alternative is the EmbeddedSTS provided by Thinktecture:
EmbeddedSts is intended to be used from an ASP.NET application that is using .NET 4.5 and the Federated Authentication Module (FAM) from WIF. It allows for a simple and easy to use STS instead of a production STS that might require installation and configuration. It does this by embedding itself a proper WS-Federation security token service within the application itself. When the ASP.NET application would normally redirect to the production STS, it will instead redirect to the EmbeddedSts. The EmbeddedSts will provide a list of users that can login and will then issue a SAML token back to the application that contains the selcted user's claims. This list of users and their associated claims is configurable in a JSON file (which can also be checked into your project, which is useful for testing).