generic tests for task input/output

[eparejatobes]

We need a generic test for checking that all inputs/outputs are present at their specified S3 locations.

[eparejatobes]

Ideally, they could be used (informally or not) as preconditions to a change in task state #1

[eparejatobes]

Waiting for #1. See

• www.scalatest.org/user_guide/sharing_fixtures

[eparejatobes]

a naive example in 13945c8#diff-793f91ce51de2bb7f92cd8ba1b7b72a1R45

[eparejatobes]

Now that I think of it, AnyTaskState can serve as a good place for putting input and output locations, which can then be used (for example) in tests. Basically it amounts to adding a Set of denotations of its input and output. A tentative list of useful tests, depending on the task state (see AnyTaskState):

• AnyTaskState check the date, suggest expiration
• Started all input locations should exist in S3 (or validate size/correcteness if they're Strings?)
• Review (see a new Review task state #5) check that all outputs exist

[eparejatobes]

This is too involved in practice. Much simpler to have as part of AnyTask#Raw denotations of its input and output, together with the task state. See #6