YAML Test Codegen

[KodrAus]

From #1 Some notes on the YAML format.

For do steps, if a body is supplied, expect it as JSON.

struct Do<'a> {
    name: &'a str,
    params: Vec<&'a str>
}

For match, is_false and is_true steps, parse to assert_eq, assuming there aren't any complex matches to deal with.

Use the free string on line 2 as either a comment on each test, or append to the test name.

There will need to be a coded response type, which should live in the types crate.

[KodrAus]

Worth looking at the C# YAML Tests for ideas on interpreting the YAML structure

[KodrAus]

This is going to depend on getting a YAML library working https://github.com/serde-rs/yaml/issues/3

[dtolnay]

@KodrAus that project looks dead. I have a working YAML library for serde at dtolnay/serde-yaml and I have updated the serde readme to refer to it. Let me know if you run into any trouble with it. The API is largely identical to serde_json.

[KodrAus]

@dtolnay Thanks! I did actually have a look at your library a little while ago and it was the one I was planning to use. Once I get a few issues with my codegen sorted I'll start working on the tests.

[KodrAus]

I think it's about time to start working on this. The aim is:

• Test against the lower level request types by default (not super worthwhile since that'll just be executing plain http requests with a body)
• Support overriding the test runner for various types, based on matching the endpoint in do to test higher-level request types. I'll probably need to make the generated code pluggable so it can receive alternative functions for things based on the endpoint.