Unit testing with Noda Time

This page is not about how Noda Time itself is tested - it's about how you to test code which uses Noda Time.


Firstly, get hold of the NodaTime.Testing assembly. It's currently fairly small, but it will no doubt grow - and it will make your life much easier. The purpose of the assembly is to provide easy-to-use test doubles which can be used instead of the real implementations.

While you can use Noda Time without dependency injection, it will make your code harder to test. Noda Time has no particular support for any specific dependency injection framework, but should be easy to configure with any reasonably-powerful implementation. (If it's not, please file a bug report.)


The most obvious dependency is a clock - an implementation of NodaTime.IClock, which simply provides "the current date and time" (as an Instant, given that the concept of "now" isn't inherently bound to any time zone or calendar). The FakeClock can be set to any given instant, advanced manually, or set to advance a given amount each time it's accessed. The production environment should normally inject the singleton SystemClock instance which simply uses DateTime.UtcNow behind the scenes.

Time zone providers and sources

For code which is sensitive to time zone fetching, an IDateTimeZoneProvider can be injected. There are currently no test doubles for this interface - please contact the mailing list with requirements if to give us feedback on exactly what you'd like provided here. The production environment should usually be configured with one of the providers in DateTimeZoneProviders.

Time zones

For time zones themselves, a fake implementation representing a time zone with a single transition between different offsets is available as SingleTransitionDateTimeZone. Creating a time zone with no transitions at all is simple via DateTimeZone.ForOffset.