WIP test: improve testing tools

[kt3k]

This resolves some TODOs in the testing library.

• Shows the ok / FAILED message in the same line as the name of the test case.
• Counts the number of filtered tests.

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Waiting for #948 to be resolved first.

[ry]

Hi @kt3k thank you but I don’t want to land this one -

#923 already addresses this counters (which I will land shortly) and this doesn’t properly solve the name-printing problem.

[ry]

I’d like the test name to be displayed before the test is run, so if it crashes there is still evidence of what caused it. Here tha name is printed after “fn()”

[hayd]

Could this instead first write to stdout instead of console.log (so as to avoid the newline)?

[kt3k]

I tried deno.stdout.write(new TextEncoder().encode('message')) to print the message without newilne, but it didn't print anything...

[ry]

@kt3k That is likely because TTYs are line buffered by default. To do this we probably need call sync(2) or set the TTY in unbuffered mode.

Maybe @piscisaureus remembers how we did this in Node...

[ry]

Upon further investigation, we are using tokio-fs's stdout, which writes to std::io::Stdout, which has a flush method (suggesting it is line buffered). If we were issuing a write syscall directly, this wouldn't happen - so my comment about needing to set the TTY into unbuffered mode was wrong.
We should probably expose that flush method as deno.stdout.flush()...

[ry]

Rust's stdout is always line buffered:
https://github.com/rust-lang/rust/blob/e1643a8968753226dab7ab3c9fee826f097550f2/src/libstd/io/stdio.rs#L344-L349
We are not so happy with this behavior and likely want an always unbuffered stdout, as in Node. Therefore to support his behavior we will need to refactor the stdout/stderr resources to use a raw file descriptor like this:

use std::os::unix::io::FromRawFd;
let stdout = File::from_raw_fd(1);

[ry]

I've opened an issue for this: #948

[kt3k]

@ry Sorry for the duplication. I'll revert that part.

[kt3k]

I will submit this again when #948 solved or when other solution available