Question

What’s the standard/recommended way to test time-dependent methods?

As an example:

I have a class Foo that has a method GetTimestamp() and GetTimestamp() should return the given time in a string that always increases lexicographically (alphabetical sort order).

What’s the best way to test this without overengineering for testing purposes?

My initial thought was to create a class constructor that accepts an IDateTimeProvider whose only property was a DateTime property, and then from the unit test I could create a dummy DateTimeProvider…

This is a simplistic case but represents what I’m wondering about.

This has a lot of other applications, such as testing date-dependent logic around leap years, etc.

Answer 1

This is a good resource:

Why there is no IDateTimeProvider in .NET and DateTime has Now getter?

It sounds like this is an OK approach.