Test that plot() does not change the user's graphical parameters

R/ternary_plot.R

@@ -16,6 +16,7 @@ setMethod(
                         panel.first = NULL, panel.last = NULL, ...) {
 
     ## Save and restore graphical parameters
+    ## pty: square plotting region, independent of device size
     old_par <- graphics::par(pty = "s", no.readonly = TRUE)
     on.exit(graphics::par(old_par), add = TRUE)
 

cran-comments.md

@@ -8,4 +8,5 @@
 
 0 errors | 0 warnings | 1 note
 
-* This is a new release.
+* This is a resubmission.
+* We checked that the plotting functions do not change the user's graphical parameters.

tests/testthat/test-par.R

@@ -0,0 +1,45 @@
+test_that("Plot", {
+  skip_on_cran()
+
+  ## Capture and cleanup plot output
+  path <- file.path(tempdir(), "Rplot.pdf")
+  on.exit(unlink(path))
+  pdf(file = path)
+
+  ## Save graphical parameters
+  old_par <- graphics::par(no.readonly = TRUE)
+
+  ## Plot...
+  ternary_plot(NULL)
+
+  ## ...changes the user's graphical parameters...
+  new_par <- graphics::par(no.readonly = TRUE)
+  # expect_identical(new_par, old_par) # Fails
+
+  dev.off()
+
+  ## ...but these are the dimensions of the plotting region
+  ## (so it should be OK?)
+  keys <- new_par[!(new_par %in% old_par)]
+  expect_named(keys, c('pin', 'plt', 'usr', 'yaxp'))
+})
+test_that("Pairs", {
+  skip_on_cran()
+
+  ## Capture and cleanup plot output
+  path <- file.path(tempdir(), "Rplot.pdf")
+  on.exit(unlink(path))
+  pdf(file = path)
+
+  ## Save graphical parameters
+  old_par <- graphics::par(no.readonly = TRUE)
+
+  ## Plot...
+  ternary_pairs(lava)
+
+  ## ...does not change the user's graphical parameters
+  new_par <- graphics::par(no.readonly = TRUE)
+  expect_identical(new_par, old_par)
+
+  dev.off()
+})