Tests for splitting output files using TimeInterval

[josuemtzmo]

Adds tests for splitting output based on time-interval, e.g.,

ow = JLD2OutputWriter(model, (; u);
                      filename = "test.jld2",
                      ...
                      file_splitting = TimeInterval(3seconds)
                      )

[glwagner]

We should definitely get TimeInterval to work. This is important! Why doesn't it work? I don't understand the reason.

[glwagner]

Let's get TimeInterval to work.

[josuemtzmo]

We should definitely get TimeInterval to work. This is important! Why doesn't it work? I don't understand the reason.

Yes, I was also surprised. I retried and now it passed the tests, so I guess at some point I was doing something weird with TimeInterval, but I'm not sure what it was. It seems to work now.

[glwagner]

Awesome! And to be more clear, I think the reason we want it to work is so that we can also reuse all the other schedules. Another reason to use it is because we may need to change TimeInterval in the future if we support different time types (for example DateTime, or other time types that solve the annoying problem of rounding error). So in all those cases it will be nice not to have to worry about different implementations of time interval schedules.

[navidcy]

lgtm

[navidcy]

@josuemtzmo could you update the first PR comment to reflect the latest status? As far as I can see there was not any new type introduced; just the tests, right?

[glwagner]

awesome contribution! I agree with @navidcy's comments but except for the cosmetic stuff it looks good

[navidcy]

Great! When all tests pass you can merge.

[navidcy]

excellent @josuemtzmo !