Conformance tests

simple.yaml.test:

```yaml

1

a=b=c=2<3;

• Identifier: 1
• EqualsSign: 1
• Identifier: 1
• EqualsSign: 1
• Identifier: 1
• EqualsSign: 1
• Integer: 1
• LessThanSign: 1
• Integer: 1
• Semicolon: 1 ... ```

test.rs:

```rust use { conformance, serdeyaml, tinyclexer::{tokenize, Token}, };

[conformance::tests(exact,

ser = serde_yaml::to_string,
de = serde_yaml::from_str,
file = "tests/simple.yaml.test")]

fn lex_tokens(s: &str) -> Vec { tokenize(s).collect() } ```

This grabs the input from between === and ---, passes it to the test function, then serializes it with the ser function. The output is grabbed from between --- and ..., then normalized by deserializing and then reserializing. The two serialized forms are compared with assert_eq!. The file path is relative to the Cargo manifest.

Any number of tests can be included in one conformance test file. The file name and the test name (above the ===) are combined and used to name the test given to the standard Rust test runner.

The ser and de functions don't have to be serde, they just have to meet the shape of fn<T>(&T) -> String for serialization and fn<T>(&str) -> Result<T, impl Error> for deserialization.

For more information, see the dev.to announcement post.