Create a testthat unit

This is a sample to show how to write a testthat unit test based on one of Animint visualizations.

Prerequisite:
- Docker and Selenium Docker Image(selenium/standalone-firefox-debug:2.53.0)
- animint2 Package
- VNC viewer(If you are using MAC or Windows)

YOUR-TEST.R

Here’s the code for Newton’s Method:

newton.method = function(
  FUN = function(x) x^2 - 4, init = 10, rg = c(-1, 10), tol = 0.001, nmax=50
) {
  i = 1
  nms = names(formals(FUN))
  grad = deriv(as.expression(body(FUN)), nms, function.arg = TRUE)
  x = c(init, init - FUN(init)/attr(grad(init), 'gradient'))
  gap = FUN(x[2])
  fx = FUN(x[1])
  
  while (abs(gap) > tol & i <= nmax & !is.na(x[i + 1])) {
    
    gap = FUN(x[i + 1])
    x = c(x, x[i + 1] - FUN(x[i + 1])/attr(grad(x[i + 1]), 'gradient'))
    fx <- c(fx, FUN(x[i + 1]))
    i = i + 1
    
    if (i > nmax) warning('Maximum number of iterations reached!')
  }
  
  x.temp = seq(rg[1], rg[2], length = abs(rg[2]-rg[1])/0.1)
  curve = data.frame(x=x.temp)
  curve$fx = as.numeric(lapply(curve$x, FUN))
  
  fx <- c(fx, FUN(x[i + 1]))
  objective <- data.frame(iteration = 1:(i+1), x = x, fx = fx)
  invisible(
    list(curve = curve, objective = objective)
  )
}

Sample renderer test code:

# Test of needed data columns in TSV files
chunk1.tsv <- file.path("animint-htmltest", "geom1_hline_contour_chunk1.tsv")
chunk1 <- read.table(chunk1.tsv, sep="\t", header=TRUE,
                     comment.char="", quote="")

Starting selenium docker image

Note: I use native Screen Sharing app on Mac as VNC.

Pull the image:

docker pull selenium/standalone-firefox-debug:2.53.0

Starting selenium docker image:

docker run -d -p 4444:4444 -p 5900:5900 selenium/standalone-firefox-debug:2.53.0

where 4444:4444 is for Selenium, and 5900:5900 is for VNC server.

Load libraries

You need to change working directory to tests directory.

library("testthat")
library("animint2")
library("RSelenium");library("XML")
setwd("testthat")
source("helper-functions.R")
source("helper-HTML.R")
source("helper-plot-data.r")

Start a Firefox browser and run test

Start a firefox browser instance on the selenium server.

tests_init("firefox")

We use the function tests_run() here.

tests_run()

Congratulations! Now you have started testing your new feature!