This PR adds a test reporter for the [Test Anything
Protocol](https://testanything.org).
It makes the following implementation decisions:
- No TODO pragma, as there is no such marker in `Deno.test`
- SKIP pragma for `ignore`d tests
- Test steps are treated as TAP14 subtests
- Support for this in consumers seems spotty
- Some consumers will incorrectly interpret these markers, resulting in
unexpected output
- Considering the lack of support, and to avoid implementation
complexity,
subtests are at most one level deep (all test steps are in the same
subtest)
- To accommodate consumers that use comments to indicate test-suites
(unspecced)
- The test module path is output as a comment
- This is disabled for `--parallel` testing
- Failure diagnostics are output as JSON, which is also valid YAML
- The structure is not specified, so the format roughly follows the spec
example:
```
---
message: "Failed with error 'hostname peebles.example.com not found'"
severity: fail
found:
hostname: 'peebles.example.com'
address: ~
wanted:
hostname: 'peebles.example.com'
address: '85.193.201.85'
at:
file: test/dns-resolve.c
line: 142
...
```