Split out of #185, which closed the R unit-test gaps. This is the one item left: R has no end-to-end tests.
Why it is its own issue
The blocker is fixture infrastructure, not test cases. pkg-py/tests/playwright/ stands up a Python Shiny app per fixture; an R suite needs an equivalent runner for R apps (shiny::runApp() in a subprocess, port allocation, readiness polling, teardown) before a single assertion can be written. That is a different kind of change from writing tests, so it did not belong in #185's PR.
What to cover
The JS bundle is byte-identical between the two packages (md5 335334fd88165d6906de2fd20c2ee174), so an R suite is not re-testing the client — it validates the R server bindings. A subset of the Python suite is enough. Python currently covers:
- module namespaces
- module dependency injection
- bookmark restore
- input-handler types
ShinyOutput
Bookmark restore and input-handler types are the highest value in R, since those are where the two servers' implementations actually differ (pkg-r/R/bookmark.R uses pinned shiny::: internals; default_input_handler() exists specifically to undo jsonlite/shiny simplification that Python never does).
Module dependency injection is likely not applicable — set_react_page()'s renderer-dependency harvesting is Shiny Express-only and has no R analogue by an explicit decision.
Notes
decisions/2026-03-17-playwright-testing-architecture.md records the recommended approach (code-gen from TypeScript) for browser testing generally; worth reading before picking a direction.- The Makefile pattern to mirror:
py-test-e2e clears the addopts that otherwise ignore the playwright/ subtree, keeping py-check-tests fast.
Split out of #185, which closed the R unit-test gaps. This is the one item left: R has no end-to-end tests.
Why it is its own issue
The blocker is fixture infrastructure, not test cases.
pkg-py/tests/playwright/stands up a Python Shiny app per fixture; an R suite needs an equivalent runner for R apps (shiny::runApp()in a subprocess, port allocation, readiness polling, teardown) before a single assertion can be written. That is a different kind of change from writing tests, so it did not belong in #185's PR.What to cover
The JS bundle is byte-identical between the two packages (
md5 335334fd88165d6906de2fd20c2ee174), so an R suite is not re-testing the client — it validates the R server bindings. A subset of the Python suite is enough. Python currently covers:ShinyOutputBookmark restore and input-handler types are the highest value in R, since those are where the two servers' implementations actually differ (
pkg-r/R/bookmark.Ruses pinnedshiny:::internals;default_input_handler()exists specifically to undo jsonlite/shiny simplification that Python never does).Module dependency injection is likely not applicable —
set_react_page()'s renderer-dependency harvesting is Shiny Express-only and has no R analogue by an explicit decision.Notes
decisions/2026-03-17-playwright-testing-architecture.mdrecords the recommended approach (code-gen from TypeScript) for browser testing generally; worth reading before picking a direction.py-test-e2eclears theaddoptsthat otherwise ignore theplaywright/subtree, keepingpy-check-testsfast.