Fix NA comparison bug in compare.character

Author: hadley

NEWS.md

@@ -3,6 +3,7 @@
 * Better default environment for `test_check()` and `test_package()` which
   allows S4 class creation in tests
 
+* `compare.character()` no longer fails when one value is missing.
 
 # testthat 0.8
 

R/compare.r

@@ -31,7 +31,9 @@ compare.character <- function(x, y, ..., max_strings = 5, max_lines = 5,
   # If they're not the same length, fallback to default method
   if (length(x) != length(y)) return(NextMethod())
 
-  diff <- x != y
+  # If vectorwise-equal, fallback to default method
+  diff <- xor(is.na(x), is.na(y)) || x != y
+  diff[is.na(diff)] <- FALSE
 
   if (!any(diff)) {
     return(NextMethod())
@@ -40,7 +42,7 @@ compare.character <- function(x, y, ..., max_strings = 5, max_lines = 5,
   width <- width - 6 # allocate space for labels
   n_show <- seq_len(min(length(diff), max_strings))
   show <- diff[n_show]
-  
+
   encode <- function(x) encodeString(x, quote = '"')
   show_x <- str_chunk(str_trunc(encode(x[show]), max_lines * width), width)
   show_y <- str_chunk(str_trunc(encode(y[show]), max_lines * width), width)

tests/testthat/test-compare.r

@@ -1,7 +1,17 @@
 context("Compare")
 
 test_that("Equal strings with different attributes are not equal", {
-
   expect_false(compare(structure("text", y = "foo"), "text")$equal)
+})
+
+test_that("different types of missing values are not equal", {
+  expect_false(compare(NA, NA_character_)$equal)
+})
+
+test_that("equal if both missing or both the same", {
+  expect_true(compare(NA_character_, NA_character_)$equal)
+  expect_true(compare("ABC", "ABC")$equal)
 
+  expect_false(compare("ABC", NA_character_)$equal)
+  expect_false(compare(NA_character_, "ABC")$equal)
 })