Testing paramaterized shiny flexdashboard apps with shinytest

davidski · February 17, 2019, 7:20pm

Is it possible to test parameterized shiny flexdashboard documents via Shinytest?

I have a flexdashboard Rmarkdown document in a package. This dashboard is exposed to end users via a package function that wraps rmarkdown::run(), passing parameters via the render_args argument that point to the correct directories for this dashboard to read. I can't find a way via ShinyDriver to set these parameters as the app is launched. Without passing the correct data file source directories, the dashboard will fail to render and launch, so ShinyDriver never gets instantiated properly.

Is there a way to pass parameters to such a shiny-powered flexdashboard? I'd love to get testing working for this document!

cderv · February 18, 2019, 7:34am

From the shinytest website, this seems possible with some conditions:

Also from the github repo, we can find the PR for this feature:

github.com/rstudio/shinytest

Add support for testing Rmd Shiny apps

rstudio:master ← rstudio:support-rmd

opened 02:28AM - 25 Aug 17 UTC

wch

+675 -97

This closes #123. It adds support for testing Rmd Shiny apps. Some examples can …be seen in the tests/testthat/recorded_tests/ directory. Some things still need to be done: - [x] Rmd test scripts currently need a `Sys.sleep()` after the `ShinyDriver$new()`, to give the server time to render the document. This should be fixed. - [x] Directory structure: If the Rmd is at, for example, `foo/app.Rmd`, then the tests are invoked with `testApp('foo/app.Rmd')`, and the test scripts and results are stored in `foo/tests`. This means it difficult to test multiple Rmd files in a directory. So we'll need to figure out a new directory structure for tests on Rmd files. - [x] If a doc has `runtime: shiny_prerendered`, it will leave behind an `.html` file and a cache directory. These should be removed after running the tests. Update: the docs should say how to modify the test script to clean up those objects. - [x] The test script currently must have a random seed for repeatable tests on Rmd apps. This seed should be added by default, and it should be well-documented that the seed is necessary. - [ ] The tests that are added to this package bring in rmarkdown and flexdashboard as Suggested packages. This seems inelegant - perhaps these tests should be moved elsewhere. - [x] For conciseness, maybe ignore the value of `input$__reactivedoc__`, or hash it?

There is an example in the repo
https://github.com/rstudio/shinytest/blob/master/tests/testthat/recorded_tests/rmd/tests/mytest.R

It is just some hints that I hope can help.

davidski · February 18, 2019, 6:01pm

Thanks for info. Unfortunately, running app$setInputs() is insufficient for my dashboard. My Flexdashboard has a parameter on the location for it's data files which has to be valid for the dashboard to knit. Without the ability to specify the render_args parameter, the ShinyDriver$new() call will fail, as the dashboard will never launch.

It sounds like ShinyTest can't currently handle this use case. I'll open an issue on the shinytest repo to track this as a feature request.

cderv · February 18, 2019, 6:09pm

For reference, the issue is

github.com/rstudio/shinytest

Pass render_args to rmarkdown::run()

opened 06:08PM - 18 Feb 19 UTC

closed 12:28PM - 20 Aug 20 UTC

davidski

feature ShinyDriver

Following up on https://community.rstudio.com/t/testing-paramaterized-shiny-flex…dashboard-apps-with-shinytest/24112 - it doesn't appear that shinytest can currently pass `render_args` to a Flexdashboard with the shiny run time. In my use case, I have parameters defined in the Flexdashboard YAML header that specify the directories to find my data files. I typically call this with a call to `rmarkdown:::run()`. There doesn't seem to be a way to pass these parameters on to my dashboard for Shinytest, which means that the app can never initialize. I'd love to be able to snapshot and test this! Thanks for the super useful package!

system · February 25, 2019, 6:22pm

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