Add basic e2e tests for state push/pull

[kmoe]

Extremely basic e2e tests for state push/pull. These would have caught the bug fixed in #316.

I wonder if StatePull should also return a state struct instead of a string.

[radeksimko]

Thanks for the test.

I wonder if StatePull should also return a state struct instead of a string.

Maybe? Depends on how we represent state elsewhere. Also there's a potential concern with scale if the state is big - maybe io.Writer interface which leaves the writing to the consumer is better?

Similarly StatePush could also take io.Reader and pass the content as STDIN.

I think we'll need to rethink these interfaces, along with Format* methods for v1.

[kmoe]

Maybe? Depends on how we represent state elsewhere.

Show() returns a *tfjson.State, which I think is reasonable. We should at least be consistent, I think.

Also there's a potential concern with scale if the state is big - maybe io.Writer interface which leaves the writing to the consumer is better?

Yes, good point... Opened #321.

I think we'll need to rethink these interfaces, along with Format* methods for v1.

Do you mean possibly removing FormatString()? We currently have both this and Format() which uses io.Reader/Writer.

[radeksimko]

Do you mean possibly removing FormatString()? We currently have both this and Format() which uses io.Reader/Writer.

Maybe - I don't have all the context and use cases in my mind right now have the confidence, but the io.Reader/Writer generally seems more scalable and universal.