test: replaces assert.throws() with common.expectsError()

[saudkhanzada]

replaces assert.throws() with common.expectsError() to check error code
and error type in parallel/test-buffer-alloc.js

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• commit message follows commit guidelines

[Trott]

CI: https://ci.nodejs.org/job/node-test-pull-request/17009/

[BridgeAR]

There is no need to use common.expectsError() to do this. assert.throws() is also able to do that. Therefore the message is a bit off. I suggest to rephrase to:
test: check for error codes in test-buffer-alloc.js

Otherwise LGTM

[Trott]

There is no need to use common.expectsError() to do this.

@BridgeAR The reason to use common.expectsError() is so that it can be cherry-picked into the 8.x-staging branch rather than requiring a backport.

Once 10.x is the oldest supported version, we can likely get rid of common.expectsError() in favor of assert.throws(). (We'll need to refactor cases where common.expectsError() returns a function, but it should be do-able.)

[trivikr]

nit: Since this error object is used multiple times in the test, it can be stored in a const.

[Trott]

CI: https://ci.nodejs.org/job/node-test-pull-request/17078/

[Trott]

CI: https://ci.nodejs.org/job/node-test-pull-request/17079/

[Trott]

Resume build: https://ci.nodejs.org/job/node-test-pull-request/17084/

[refack]

The reason to use common.expectsError() is so that it can be cherry-picked into the 8.x-staging branch rather than requiring a backport.

I remember we used to use common.expectsError for checking NodeErrors that have an error code, while assert.throws was the legacy usage. And we used that distinction to track where we still throw "old" errors.
Was that effort completed?

[BridgeAR]

@refack assert.throws() became significantly more powerful in the meanwhile. It now behaves very similar to common.expectsError(). But @Trott is correct that these changes were not yet backported to 8 and it's easier to backport everything with the current notation until those features landed in 8 as well.

[Trott]

Landed in 9782ce2.

Thanks for the contribution! 🎉

(If you're interested in other possible contributions to Node.js but don't have a good idea of where to start looking, some ideas are posted at https://www.nodetodo.org/next-steps/.)