tests/testthat/test_replyr_mapRestrictCols.R

In replyr: Patches to Use 'dplyr' on Remote Data Sources

library('replyr')

context("mapRestrictCols")

test_that("test_replyr_mapRestrictCols.R", {
  # an external function with hard-coded column names
  DecreaseRankColumnByOne <- function(d) {
    d$RankColumn <- d$RankColumn - 1
    d
  }

  # our example data, with different column names
  d <- data.frame(
    Sepal_Length = c(5.8, 5.7),
    Sepal_Width = c(4.0, 4.4),
    Species = 'setosa',
    rank = c(1, 2)
  )
  #print(d)

  # map our data to expected column names so we can use function
  nmap <- c(
    GroupColumn = 'Species',
    ValueColumn = 'Sepal_Length',
    RankColumn = 'rank'
  )
  #print(nmap)
  dm <- replyr_mapRestrictCols(d, nmap)
  #print(dm)

  # can now apply code that expects hard-coded names.
  dm <- DecreaseRankColumnByOne(dm)

  # map back to our original column names (for the columns we retained)
  invmap <- names(nmap)
  names(invmap) <- as.character(nmap)
  #print(invmap)
  # Note: can only map back columns that were retained in first mapping.
  replyr_mapRestrictCols(dm, invmap)

})