Expand tests

tests/iteration.R

@@ -4,46 +4,66 @@
 ## These tests pass with both compiler::enableJIT(0) and compiler::enableJIT(3)
 
 sequence_generator_factory <- function(start, end, step = 1L) {
- if(missing(end)) {
+ if (missing(end)) {
  end <- start
  start <- 1L
  }
  stopifnot(length(start) == 1L,
  length(end) == 1L,
- length(stop) == 1L)
+ length(step) == 1L)
+
+ function() {
+ if (start > end)
+ return(NULL) # iterator exhausted
 
- function(){
- if(start > end) return(NULL)
  on.exit(start <<- start + step)
  start
  }
 }
 
 
 x <- structure(list(), class = 'foo')
-as.iterable.foo <- function(x) 1:3
+as.iterable.foo <- function(x) c("a", "b", "c")
 
-## pass an object with an `as.iterable` method to `for`
-counter <- 0L
-for(i in x){
- counter <- counter + 1L
- print(i)
+## pass to `for` an object with an `as.iterable()` method
+observed <- textConnection(NULL, "w", local = TRUE)
+for (elem in x) {
+ writeLines(elem, observed)
 }
-stopifnot(i == 3L, counter == 3L)
+stopifnot(
+ identical(elem, "c"),
+ identical(textConnectionValue(observed), c("a", "b", "c"))
+)
+
+observed <- textConnection(NULL, "w", local = TRUE)
 
+## pass to `for` a closure
+for (elem in sequence_generator_factory(4)) {
+ writeLines(paste("elem =", elem), observed)
+}
 
-## pass a function to `for`
-for(i in sequence_generator_factory(4))
- cat("i = ", i, "\n")
 
-stopifnot(i == 4L)
+stopifnot(
+ identical(elem, 4L),
+ identical(
+ textConnectionValue(observed),
+ c("elem = 1", "elem = 2", "elem = 3", "elem = 4")
+))
 
-## pass to `for` an object with an `as.iterable` method that returns a function
+observed <- textConnection(NULL, "w", local = TRUE)
+
+## pass to `for` an object with an `as.iterable()` method that returns a closure
 as.iterable.foo <- function(x) {
  sequence_generator_factory(11, 13)
 }
 
-for(i in x)
- cat("i = ", i, "\n")
+for(elem in x) {
+ writeLines(paste("elem =", elem), observed)
+}
 
-stopifnot(i == 13)
+stopifnot(
+ identical(elem, 13L),
+ identical(
+ textConnectionValue(observed),
+ c("elem = 11", "elem = 12", "elem = 13")
+))