test: allow passing args to executable

[stefanmb]

To set up CI jobs for #5181 there has to be a way to pass an argument to the Node executable at test time. The makefile supports the TEST_CI_ARGS environment variable, but the test harness (test.py) provides no facility to further pass the argument to the executable under test.

There is a "--special-command" argument, but it is only able to suffix or prefix the existing command line in the format [node, test] so it is insufficient to produce commands in the form [node, node_args, test]. In this PR I've introduced an extra argument to the test harness called --node-args which can be used to pass commands verbatim.

Some support for this feature already existed in test/init.py in the form of the "additional" argument, however none of the individual test modules' testcfg.py make use of it, so in the interest of minimal footprint I've opted to directly set this value form test.py, instead of passing it through as a constructor argument.

There is an additional complication in "test-cluster-debug-port.js" which for reasons that are unclear refuses to run if any arguments are passed to the process. I've simply relaxed this requirement.

[stefanmb]

@indutny@mhdawson I'd appreciate any comments regarding the impact on #5181, thanks.

[bnoordhuis]

LGTM. Maybe break up the long line. CI: https://ci.nodejs.org/job/node-test-pull-request/1731/

[Fishrock123]

Can't you already pass arguments to node by having a comment at the top of the file ala https://github.com/nodejs/node/blob/master/test/parallel/test-repl-persistent-history.js#L3 ? Am I missing something?

[stefanmb]

@Fishrock123 That facility is provided in test/testpy/init.py by statically scanning the source of each file, which is similar to what I'm proposing here, but not identical. The requirement here is to be able to dynamically choose whether to pass a flag to every test, or not, at runtime. Specifically, for FIPS builds (which now default to FIPS off) the test suites have to be run twice, once with FIPS off, and once with FIPS on. This can be achieved by passing --enable-fips to the Node executable under test, using the "additional_flags" variable already present in test/testpy/init.py

Further details are included in #5181.

[Fishrock123]

Ah, makes sense. 👌

[stefanmb]

@bnoordhuis I split the function signature as indicated, thanks.

[Trott]

As much as I dislike adding more stuff to test.py, it's hard to argue with the need here. LGTM

[mhdawson]

LGTM. going to land

[mhdawson]

CI run - https://ci.nodejs.org/job/node-test-pull-request/1751/

[mhdawson]

Only one failure in CI which is unrelated to this change - reopened #5184 and added link to failure

[mhdawson]

Landed as 23a584d

[stefanmb]

This PR introduced a regression that is fixed in #5446.