currentTime strategy constraint doesn't work

[tlevesque-ueat]

Describe the bug
If I create a strategy with a DATE_AFTER constraint on currentTime, with a date in the past, the feature flag is always considered disabled.
The same feature flag works fine on the frontend with unleash-proxy-client-js.

To Reproduce
Steps to reproduce the behavior:

1. Create a feature flag with a gradual rollout strategy with 100% rollout
2. Add a constraint on currentTime with DATE_AFTER and a date in the past
3. In the app, call IUnleash.IsEnabled("MyFeatureFlag")
4. It always returns false, whether the current date is before or after the specified date
5. Remove the currentTime constraint
6. Now IUnleash.IsEnabled("MyFeatureFlag") returns true

Expected behavior
IUnleash.IsEnabled("MyFeatureFlag") should return true if the current date is after the specified date

Screenshots

Desktop (please complete the following information):

• OS: Ubuntu (deployed application), Windows (for local development)
• Browser: irrelevant (server application)
• Version: 4.1.13

[tlevesque-ueat]

I think the problem is here:

unleash-client-dotnet/src/Unleash/Strategies/Constraints/DateConstraintOperator.cs

Lines 26 to 28 in 43caba8

	contextDate = context.CurrentTime;
	if (!contextDate.HasValue)
	return false;

If context.CurrentTime is not set, it should use the current time. That's what the documentation says anyway:

[tlevesque-ueat]

In fact, shouldn't it use context.CurrentTime only if constraint.ContextName is "currentTime"?
It seems a little strange that it would fall back to context.CurrentTime if I specified "myCustomDate" as the context name...

[tlevesque-ueat]

I submitted a PR
#246

[daveleek]

thank you for raising this and for providing a clear bug report + a PR @tlevesque-ueat! We'll have a look and get back to you!