vec_equal_tol() checks equality of infinite values

Fixes #789

NEWS.md

@@ -1,5 +1,7 @@
 # testthat (development version)
 
+* `expect_equal()` compares infinite values correctly (#789).
+
 * `expect_output()` gains `width` argument, allowing you to control the 
   output width. This does not inherit from `getOption("width")`, ensuring 
   that tests return the same results regardless of environment (#805).

R/compare.R

@@ -91,5 +91,7 @@ vector_equal <- function(x, y) {
 }
 
 vector_equal_tol <- function(x, y, tolerance = .Machine$double.eps ^ 0.5) {
-  (is.na(x) & is.na(y)) | (!is.na(x) & !is.na(y) & abs(x - y) < tolerance)
+  (is.na(x) & is.na(y)) |
+    (!is.na(x) & !is.na(y)) & (x == y | abs(x - y) < tolerance)
+
 }

tests/testthat/test-compare.R

@@ -8,3 +8,15 @@ test_that("list comparison truncates to max_diffs", {
   lines2 <- strsplit(compare(x, y, max_diffs = 99)$message, "\n")[[1]]
   expect_length(lines2, 100)
 })
+
+test_that("vector_equal_tol handles infinity", {
+  expect_true(vector_equal_tol(Inf, Inf))
+  expect_true(vector_equal_tol(-Inf, -Inf))
+  expect_false(vector_equal_tol(Inf, -Inf))
+  expect_false(vector_equal_tol(Inf, 0))
+})
+
+test_that("vector_equal_tol handles na", {
+  expect_true(vector_equal_tol(NA, NA))
+  expect_false(vector_equal_tol(NA, 0))
+})