stream, test: Add test for _writableState state machine

[mcollina]

• Version: all
• Platform: all
• Subsystem: stream, test

Part of #8644

stream._writableState.needDrain
stream._writableState.ending
stream._writableState.ended
stream._writableState.finished

node/lib/_stream_writable.js

Lines 46 to 52 in 774146d

	this.needDrain = false;
	// at the start of calling end()
	this.ending = false;
	// when end() has been called, and returned
	this.ended = false;
	// when 'finish' is emitted
	this.finished = false;

cc @Fishrock123 @nodejs/streams

[corykitchens]

@mcollina @Fishrock123 I'd love to take a shot at this as a first contribution. Who would be the main point of contact in regards to questions/comments/etc?

[mcollina]

You can target @nodejs/stream, or myself.

[italoacasas]

@corykitchens I already have 3/4 PR open, the only available is the needDrain flag, if you want to do it let me know and I just move to another Issue.

[mcollina]

@italoacasas unfortunately @nodejs/streams or myself was not tagged, and github do not send notification of open PR referencing an issue, sigh.

I'll get them reviewed asap.

[corykitchens]

@italoacasas Yes sounds good, I'll work on whatever needs to get done.

[mcollina]

@italoacasas Can you please just use stream for the tests, instead of files? It makes things harder to port to readable-stream otherwise.

[italoacasas]

@corykitchens it's at to you, just let me know.

@mcollina I'll make the change tonight, thanks for the feedback.

[mcollina]

@italoacasas can you please add something in your tests, they all look the same for those variables, but they are not. I would really like to see a tests where those variables are different.