ROpenSci Community Call: Last Night, Testing Saved my Life

class: title-slide, nologo, nobar

![:spacer 10px]()

![:img left: 500px, top: 75px, 200px, , ](./Figures/logos/ubrandon.png)
![:img left: 125px, top: 40px, 350px, , ](./Figures/logos/logo_eg.png)

![:spacer 100px]()

# Last Night, Testing Saved my Life
### Experiences of a biologist

![:spacer 30px]()

![:info h, , bottom: 10px]()

---
# My Goals

.center[**How I hope you'll feel about testing**]

![:img center, bottom: 25px, 70%, , <a href = "https://www.instagram.com/birdstrips/">Birdstrips on Instagram</a>](https://i.redd.it/9gi734pdzz611.jpg)

???
My experiences: I.e. Not a computer programmer! Learned a bit piecemeal, this always learning new things, definitely not an expert.

---
# Different Kinds of Testing

(According to Steffi)

## Due Diligence (Data-testing)
- Double checking output as part of an analysis
- Sometimes interactive only
- Sometimes Rmd Report for posterity (and reproducibility)

## Automated Package Tests
- Rigorous, repeated, and automatic tests of package functionality
- Often local **and** remote (i.e. CRAN, Travis Ci, AppVeyor, [R-hub](https://builder.r-hub.io/))

![:spacer 15px]()

> For this talk, **Testing = Automated Package Tests**

---
# Why I Started Testing

## Post-Doc on RFID project
- Summarize RFID data 
  - Movement between feeders
  - Time spent at a feeder
  - etc.
- Started with small scripts
- Created my first package ([`feedr`](https://github.com/animalnexus/feedr)!)

![:img right: 15px, bottom: 50px, 24%, , ](./Figures/feeder_vert.jpg)
![:img right: 325px, bottom: 50px, 24%, , ](./Figures/bcch_rfid.jpg)
.footer-right[Jacob Bailey]

## But!
- My colleagues trusted me too much
- Package was getting big and worrisome
  - Mistakes
  - Breaking old code as adding new code

???
About 4 years ago got a post-doc to

---
class: split-75
# How I Started Testing

.columnl[
- Hadley's "R packages" book chapter on Testing*
- Used [`testthat`](https://github.com/r-lib/testthat) package
- Series of test files (e.g., `test_utils.R`) in `tests/testthat` folder

.footer[*Now [2nd edition by Hadley Wickham and Jennifer Bryan](https://r-pkgs.org/)]
]

.columnl[

![:spacer 5px]()

```r
test_that("check_normals() takes 'YYYY-YYYY'", {
  expect_silent(check_normals("1981-2010"))
  expect_error(check_normals("1981 2010"), "text string in the format")
  expect_error(check_normals("1981/2010"), "text string in the format")
  expect_error(check_normals(1981), "text string in the format")
})
```
![:img right: 25px, bottom: 140px, 20%, , ](./Figures/logos/testthat.jpg)
]

.columnl[
- Automatically run by processes that build the package
 - R CMD CHECK, CRAN, [R-hub](https://builder.r-hub.io/)
 - Travis CI, AppVeyor

]

---
class: split-50
# Why I Keep Testing
## `meritget`

![:img right: 25px, bottom: 25px, 45%, , ](./Figures/meritget.png)

.columnl[
> A reward you get that has no value beyond the fact that it's a reward!
]

???
I recently learned what a meritget is from Charles Gray on twitter. And although I'm still a bit hazy, I'm pretty sure it is a reward you get, that has no value, beyond the fact that it's a reward and therefore makes you feel better. I think it comes from the achievements you can unlock in most video games these days.

---
# Why I Keep Testing
## `meritget`

![:img center, bottom: 50px, 60%, , ](./Figures/failure.png)

???
I love the little pep-talk messages I get when testing

---
# Why I Keep Testing
## `meritget`

![:img center, bottom: 15px, 55%, , ](./Figures/success.png)

![:box 20%, 40%, 30%](Sometimes it tells me I'm a Coding Rockstar!)

???
I love the little pep-talk messages I get when testing

---
# Why I Keep Testing
## `meritget`

![:img center, bottom: 35px, 60%, , ](./Figures/praise.png)

.footer[<https://github.com/r-lib/testthat/blob/master/R/praise.R>]

--
![:img center, bottom: 35px, 60%, , ](./Figures/praise2.png)

---
# Why I Keep Testing

> "Testing your code can be painful and tedious, but it greatly increases the quality of your code"  
>   .small[*`testthat` README on GitHub*]

![:spacer 30px]()

.center[
Too many times I thought:

![:spacer 15px]()

.medium[**I don't need to test that, it couldn't have broken anything!**]
]
--

![:spacer 15px]()

.center[
and was so very very wrong!
]

---
class: space-list
# Why I Keep Testing

## Problem solving
- Took over development of a package
  - No tests to start, but really helpful to add tests as I made changes
- Bug fixing
  - Writing tests to check that bug fixes worked

## Organization
- I use `testthat` tests even for long-running local tests that don't run remotely
  - Keeps me organized
- Test systematically for weird/unexpected input 
  - Make sure messages/warnings/errors show up where they should

???
Sometimes the logic of a function gets a bit complex, so it can be useful 
to have simple tests to make sure different situations are clearly dealt with

---
class: space-list
# Why I Keep Testing

## Remote Testing
- Testing packages on other operating systems
  - Travis Ci, AppVeyor, [R-hub](https://builder.r-hub.io/)

![:img left: 200px, bottom: 15px, 14%, , ](./Figures/logos/mac.svg)
![:img center, bottom: 15px, 15%, , ](./Figures/logos/windows.svg)
![:img right: 200px, bottom: 15px, 13%, , ](./Figures/logos/linux.svg)

--
![:box 50%, 50%, 25%](Windows I'm looking at YOU!)

---
class: space-list
# Why I Keep Testing

## Remote Testing
- Testing packages on other operating systems
  - Travis Ci, AppVeyor, [R-hub](https://builder.r-hub.io/)
- Using CRON scheduling on Travis Ci to check on and catch changing data sources  
  - e.g., run tests every couple of weeks for [`weathercan`](https://github.com/ropensci/weathercan)

---
# Problems with Testing

## Testing tests??!?!!
- Trouble shooting tests can take time
- Sometimes need to create special (small) datasets for testing (speed up testing)
- Sometimes complex operations take time to figure out how to test

![:img center, bottom: 15px, 68%, , <a href = "https://www.instagram.com/birdstrips/">Birdstrips on Instagram</a>](./Figures/birdstrips - I got this.jpg)

---
class: space-list

# Problems with Testing

## Where it's hard to use it
- Difficult with shiny apps
  - But see: [`shinytest`](https://github.com/rstudio/shinytest), [`RSelenium`](https://github.com/ropensci/RSelenium)
- Difficult where credentials are needed
  - There are ways of adding credentials to online test suites
  - Create sample accounts with open credentials
  - Test secured credentials locally

![:img right: 0, bottom: 0, 30%, , ](./Figures/birdstrips - crow.jpg)

.footer[[Birdstrips on Instagram](https://www.instagram.com/birdstrips)]

---
class: split-70
# Final Tips

- Time consuming, but worth it!
- Start slowly
- Use a coverage metric (e.g., [codecov.io](http://codecov.io))
- Also test for wonky input
- Number test files so they run in order  
  - e.g., `test_01_base.R`, `test_02_main.R`
- Checkout the resources in this Community Call

![:img right: 0, bottom: 0, 30%, , ](./Figures/birdstrips - crow.jpg)

.footer[[Birdstrips on Instagram](https://www.instagram.com/birdstrips)]

![:spacer 30px]()

.columnl[
.center[
## .rblue[Thank you!]
]]

![:img right: 25px, top: 125px, 350px, , ](./Figures/logos/logo_eg.png)
![:info v, right: 25px, bottom: 275px]()

.footer-right[Compiled on 2019-12-04]

.footer[
Presentation Available: <https://steffilazerte.github.io/Presentations/> 
Slides created with the R package [xaringan](https://github.com/yihui/xaringan), using [remark.js](https://remarkjs.com), [knitr](http://yihui.name/knitr), and [R Markdown](https://rmarkdown.rstudio.com) ]