Drives the real popup in a real Firefox with dist/firefox/ installed as an
unpacked MV2 temporary add-on via geckodriver. make test-e2e-firefox, outside
make check like the Chrome suite. Zero npm dependencies: plain fetch and
child_process against geckodriver's HTTP API. Base image, Firefox tarball and
geckodriver are each pinned by digest and verified at build time.
Error capture reads the privileged console service through Marionette's chrome
context, not WebDriver BiDi. BiDi delivers nothing at all for extension pages,
so a BiDi-based harness would observe zero events and report success -- the
vacuous-check shape this repo has shipped twice. Both the driver and the README
say so where someone would be tempted to simplify.
Demonstrated to discriminate: a background page that throws at the top of the
file, a missing import, and an async throw where every UI assertion still
passes each fail the run.
Three limits are measured and documented rather than papered over: capture is
poll-based so an error is attributed to a step, not a moment; the console ring
buffer holds 250 messages and evicts the oldest, measured against a clean-run
peak of 4; and the drained window ends roughly 1.5s after the last step, with
observed jitter rather than a hard boundary. Content-script capture is marked
unverified because --network none leaves no page to inject into, and that same
choice inverts coverage of network-dependent code.
