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Barret Schloerke: Lessons Learned Testing 2500+ Shiny Apps Every Day

About the Talk: The Shiny team tests 2500+ different combinations of Shiny Applications, R versions, and operating systems to verify no feature regressions occur within the bleeding edge of the Shiny-verse. Over the past few years, we have learned a few lessons to keep our tests robust and honest. There is a non-zero chance that a test failure is not your fault. When working with CI systems, external influences such as installation failures or slower computing power will prevent tests from executing properly. A picture is worth a thousand tests but visual testing is known to have a non-zero false-positive rate. To address this, we have utilized threshold based image comparisons for flaky tests. We have found that it is best to test the minimal amount of content where possible. Changes in App package dependencies can produce unintended changes in expected outputs. These hard learned lessons have reduced unreliable test results allowing the Shiny team to quickly respond to feature regressions.

Speaker’s bio: Dr. Barret Schloerke is a Software Engineer at Posit. He currently develops and maintains many R packages in the Shiny ecosystem at RStudio including shiny, reactlog, plumber, learnr, leaflet, and shinyloadtest. Dr. Schloerke received his PhD in Statistics from Purdue University under the direction of Dr. Ryan Hafen and Dr. William Cleveland, specializing in Large Data Visualization

Barret Schloerke, Shiny Team

Advanced R Markdown 2-day Workshop - rstudio::conf(2019L)

What is the 2-day Advanced R Markdown Workshop? That’s a great question, I’m glad you asked.

This is a two-day hands-on workshop based on the book “R Markdown: The Definitive Guide”.

This workshop is designed for those who want to take their R Markdown skills to the next level. We’ll talk about many low-level details in the rmarkdown package and the whole R Markdown ecosystem. The two goals of this workshop are: 1) learn how to fully customize R Markdown output (HTML, LaTeX/PDF, Word, and PowerPoint); and 2) learn more about existing R Markdown extensions in the ecosystem, such as flexdashboard, bookdown, blogdown, pkgdown, xaringan, rticles, and learnr. We will also talk about how to use or develop new language engines (languages that are not R), how to develop HTML widgets, and integrate Shiny with R Markdown.

You should take this workshop if you have experience programming in R and want to learn how to take advantage of the amazing breadth and depth of R Markdown. You’ll get the most from it if you enjoy learning how R Markdown works under the hood (which will involve reading some source code), and are seriously interested in hacking (playing) with HTML, JavaScript, CSS, LaTeX, and command-line tools. We will give minimal tutorials on these languages and tools in the workshop, but it may be easier for you to keep pace with the instructor if you already know them before.

This workshop is led by Yihui Xie, Software Engineer and Data Scientist at RStudio. Yihui is the main author of the open-source knitr package for reproducible research and dynamic report generation. He has also created and co-authored several other R packages, including rmarkdown, bookdown, blogdown, xaringan, tinytex, DT, shiny, and leaflet. He has authored and co-authored four books: Dynamic Documents with R and knitr, bookdown: Authoring Books and Technical Documents with R Markdown, blogdown: Creating Websites with R Markdown, and R Markdown: The Definitive Guide.

Speakers: Yihui Xie and Alison Hill with guest lecturers Jiena Gu and Hao Zhu