1756430 - Doc for run-sequentially incorrectly mentions thread-safety

Status: NEW

(Testing :: XPCShell Harness, defect, P2)

Description

[Gerald Squelart (he/him) (not at Mozilla since 2022-09-15)]

https://searchfox.org/mozilla-central/rev/211649f071259c4c733b4cafa94c44481c5caacc/testing/docs/xpcshell/index.rst#644-646 :

"run-sequentially" basically tells the harness to run the respective test in isolation. This is required for tests that are not "thread-safe".

However, xpcshell tests actually run in separate processes, so literal thread safety is not an issue.
I believe that this option is more about the shared environment in this multiple tests may run, e.g., files at a given location, Windows registry, web servers, etc.
I think the documentation should be updated to better reflect that.

(I don't know the exact details, so I don't want to suggest exact wordings that could be incorrect as well.)

Also related, https://firefox-source-docs.mozilla.org/build/buildsystem/test_manifests.html?highlight=run%20sequentially#recognized-metadata talks about "run-sequentially" as being used by different test systems, including some where thread-safety would actually apply, but AFAIK only xpcshell manifests understand this option.
This has led to an incorrect (but probably harmless) use in https://phabricator.services.mozilla.com/D89081#inline-506418
It would be good to review this as well, here or in another bug.

Comment 1

[BugBot [:suhaib / :marco/ :calixte]]

The severity field is not set for this bug.
:jmaher, could you have a look please?

For more information, please visit auto_nag documentation.