introduce TermLike trait; add InMemoryTerm

[chris-laplante]

These changes make it possible to write tests that compare the visual output of progress bars to expected output.

The TermLike trait provides a common abstraction over the console::Term type and the new InMemoryTerm. The trait is made public so that users can develop their own custom draw targets, should the need arise.

InMemoryTerm is basically just a vector of lines, with a cursor that tracks the current line.

Still to-do:

• Document TermLike trait
• De-duplicate code in InMemoryTerm::write_line and InMemoryTerm::write_str
• Add a method to InMemoryTerm to expose the buffer contents
• Add a method to InMemoryTerm to reconstitute buffer contents as String (will replace the buf_contents method in test module)

[djc]

As I'm pretty busy, I'm going to default to not reviewing this until it's no longer a draft. If you'd like to have feedback (ideally on some specific aspect of the code/design) sooner, please ping me!

[chris-laplante]

As I'm pretty busy, I'm going to default to not reviewing this until it's no longer a draft. If you'd like to have feedback (ideally on some specific aspect of the code/design) sooner, please ping me!

Sounds good, I need to fix some issues with it anyway. Thanks!

[chris-laplante]

I'd say this is ready :).

[chris-laplante]

@djc I'd say this is ready. Your recent changes did not let me avoid using Box, but actually we wouldn't have wanted to avoid it anyway. My intention was always that users could implement TermLike on their own types and use them freely.

[djc]

Would you mind squashing all the fix commits into the original commits so that the commits are easier to review?

[chris-laplante]

Would you mind squashing all the fix commits into the original commits so that the commits are easier to review?

Sure thing, done.

[djc]

Do you have a use case for this outside testing?

[chris-laplante]

Not really, so I suppose we could just put vt100 behind dev-dependencies and get rid of the feature.

[djc]

Yes, please.

[chris-laplante]

Hmm there's an issue with that. The 1.51 version of Rust doesn't support 2021 edition, but vt100 uses that. As a feature, I was able to tweak the GitHub workflow to exclude the feature being used with 1.51. But I don't think that's possible if vt100 is just a dev-dependency. If we want to support 1.51 I think in_memory will have to be a feature, unless there is a way I'm not seeing to limit a dev-dependency to only certain compiler versions.

[djc]

(And please squash "reorder items" into "add InMemoryTerm".)

[djc]

Thanks for all the work on this!