Support tests from https://github.com/BurntSushi/toml-test

[orchestr7]

Need to create an adaptor test framework that will deserialize toml to class and after that serialize this class to json, so we will be able to adopt these tests in our library.

Test base: https://github.com/BurntSushi/toml-test

[bishiboosh]

@akuleshov7 I've looked into it a little bit, and the main problem is that if we use the tool provided by toml-test, we don't know the shape of the data in the TOML. So, the way I see it, there are two possibilities:

• copy all the tests, and create the classes for each test
• have a way of parsing the TOML to an intermediate format (like JSON does with Json.parseToJsonElement), and then be able to translate this format into JSON

[orchestr7]

Hm, @bishiboosh, and how about making a decoding with TOML, then make encoding of the resulted data with JSON and then compare results as JSON strings?

[bishiboosh]

The fact is that to decode from TOML with ktoml, we need the class representation. The toml-test tools does not provide us with that, only the TOML file. The only ways I see of dealing with that input is like I said in my message, either copy all the tests and do the work done in toml-test ourselves (just use the test base), or implement a way to transform a TomlNode into a JsonElement (which could then be transformed to its JSON string representation)

[gildor]

I'm planning to work on this, but use official https://github.com/toml-lang/toml-test

The approach I'm going with:

1. Add toml-lang/toml-test as a git submodule
2. Write a small CLI decoder that uses TomlParser.parseString() to get the AST, then walks the TomlNode tree to produce the tagged JSON format toml-test expects - no @serializable classes needed, just some code for pattern matching on TomlValue subclasses
3. Run toml-test test -decoder=... to get a baseline of what passes/fails

So I hope to bypass the serialization API entirely and work with the parser's AST directly, just to have one more layer of validation

I just want to get multi-line inline tables from TOML 1.1, but I'm not comfortable to contribute without test harness for this, and toml-test already supports it, so I start experiment with it and see how it would og