Improve expect_setequal() implementation

To help improve failures on CRAN

Author: hadley

R/expect-setequal.R

@@ -35,8 +35,8 @@ expect_setequal <- function(object, expected) {
     warn("expect_setequal() ignores names")
   }
 
-  act_miss <- setdiff(act$val, exp$val)
-  exp_miss <- setdiff(exp$val, act$val)
+  act_miss <- unique(act$val[!act$val %in% exp$val])
+  exp_miss <- unique(exp$val[!exp$val %in% act$val])
 
   if (length(exp_miss) || length(act_miss)) {
     fail(paste0(

tests/testthat/_snaps/expect-setequal.md

@@ -24,6 +24,13 @@
     * Only in `expected`: 3
 
 
+---
+
+    c("a", "a") (`actual`) and c("b", "b", "b") (`expected`) don't have the same values.
+    * Only in `actual`: "a"
+    * Only in `expected`: "b"
+    
+
 # truncates long vectors
 
     1:2 (`actual`) and 1:50 (`expected`) don't have the same values.

tests/testthat/test-expect-setequal.R

@@ -15,6 +15,12 @@ test_that("truncates long differences", {
   expect_match(cnd$message, "...")
 })
 
+test_that("can compare data frames", {
+  # this isn't really a legit use case but one package does it
+  df <- data.frame(x = 1:10, y = 10:1)
+  expect_success(expect_setequal(unname(df), unname(df)))
+})
+
 test_that("warns if both inputs are named", {
   expect_warning(expect_setequal(c(a = 1), c(b = 1)), "ignores names")
 })
@@ -29,6 +35,9 @@ test_that("useful message on failure", {
   expect_snapshot_failure(expect_setequal(1:2, 2))
   expect_snapshot_failure(expect_setequal(2, 2:3))
   expect_snapshot_failure(expect_setequal(1:2, 2:3))
+
+  # doesn't repeat values
+  expect_snapshot_failure(expect_setequal(c("a", "a"), c("b", "b", "b")))
 })
 
 test_that("truncates long vectors", {