test: improve test-cluster-net-send.js

[akito0107]

Checklist

• make -j8 test (UNIX), or vcbuild test nosign (Windows) passes
• commit message follows commit guidelines

Affected core subsystem(s)

test, cluster

Description of change

This commit improves test-cluster-net-send as below;

• use port 0 instead of common.PORT
• use common.mustCall
• use assert.strictEqual instead of assert.equal
• change var to const or let (if possible)
• change function to arrow function

This is a part of Code And Learn at NodeFest 2016 Challenge
nodejs/code-and-learn#58

[shigeki]

CI submitted by @mscdex was running on https://ci.nodejs.org/job/node-test-pull-request/4828/ . Two tests were failed, one is due to missing g++ in CentOS7-64 build env and others Jenkins error on armv8. Others are fine. LGTM.

[cjihrig]

Instead of 127.0.0.1, couldn't you use server.address().address?

[cjihrig]

LGTM, but it looks like there are a few other improvements that could be made to this test (var -> const, common.mustCall(), assert.strictEqual(), etc.).

[akito0107]

@cjihrig
Thank you for your advice ! I fixed it !

[santigimeno]

Now that you have added the common.mustCall wrapper I think you can remove the called variable.
Also, though highly unlikely, the data listener could be called more than once, so I would check for the data validity in the end listener.

[cjihrig]

Yes, drop the called variable and the process.once('exit', ...), move the common.mustCall() from the data handler to the end handler, and do a concatenation in the data handler.

[cjihrig]

Isn't this unreachable code?

It would be better to have the process exit naturally, rather than call process.exit().

[cjihrig]

Can you add common.mustCall() here too. Otherwise, there is no guarantee that the process.once('message', ...) handler is added.

[jasnell]

common.mustCall() here as well.

[akito0107]

@cjihrig @santigimeno @jasnell
Thank you all! I fixed it.

[shigeki]

CI is running again on https://ci.nodejs.org/job/node-test-pull-request/4909/ .

[targos]

CI: https://ci.nodejs.org/job/node-test-pull-request/5003/

[targos]

The test fails on Windows: https://ci.nodejs.org/job/node-test-binary-windows/4954/RUN_SUBSET=3,VS_VERSION=vs2015,label=win2008r2/tapTestReport/

Example output on my PC:

[15828] master
[15660] worker
events.js:160
      throw er; // Unhandled 'error' event
      ^

Error: connect EADDRNOTAVAIL :::62283
    at Object.exports._errnoException (util.js:1022:11)
    at exports._exceptionWithHostPort (util.js:1045:20)
    at TCPConnectWrap.afterConnect [as oncomplete] (net.js:1090:14)

[jasnell]

@akito0107 can you please take a look at the windows test failure?

[akito0107]

@jasnell
Sorry for late.

This error might be caused by using sever.listen(0), so, I restored sever.listen(0) to server.listen(common.PORT).
I would like to check Windows CI test is passed.

[gibfahn]

I think this is the same issue as the one I saw in #10854

If so, the problem is that you can't use server.address().address here. You should be listening on 0 (i.e. all IPv6 and IPv4 addresses), in which case server.address().address resolves to ::. On linux this sometimes resolves to 127.0.0.1 if there is no IPv6 support on the machine, but this isn't the case on all platforms.

Changing to:

-  server.listen(common.PORT, () => {
-    socket = net.connect(server.address().port, server.address().address,
+  server.listen(0, () => {
+    socket = net.connect(server.address().port, 'localhost',

should fix the issue on all platforms. localhost should always resolve to either 127.0.0.1 or :: (either of which is fine).

cc/ @cjihrig

[jasnell]

Ping... status update on this one?

[fhinkel]

There hasn't been any activity here. I'm closing this. Feel free to reopen (or ping a collaborator) if I closed this in error.