Use correct paste0() argument

And add an explicit test for the behaviour

Author: hadley

R/expect-constant.R

@@ -86,7 +86,7 @@ expect_waldo_constant_ <- function(
     msg <- c(
       sprintf("Expected %s to be %s.", act$lab, exp$lab),
       "Differences:",
-      paste0(comp, collpase = "\n")
+      paste0(comp, "\n")
     )
     fail(msg, info = info, trace_env = trace_env)
   } else {

R/expect-equality.R

@@ -151,7 +151,7 @@ expect_waldo_equal_ <- function(
     msg <- c(
       sprintf(msg, act$lab, exp$lab),
       "Differences:",
-      paste0(comp, collpase = "\n")
+      paste0(comp, "\n")
     )
     fail(msg, info = info, trace_env = trace_env)
   }

tests/testthat/_snaps/expect-equality.md

@@ -40,6 +40,26 @@
       Differences:
       Types not compatible: double is not character
 
+# correctly spaces lines
+
+    Code
+      expect_equal(list(a = 1), list(a = "b", b = 10))
+    Condition
+      Error:
+      ! Expected `list(a = 1)` to be equal to `list(a = "b", b = 10)`.
+      Differences:
+      `actual` is length 1
+      `expected` is length 2
+      
+      `names(actual)`:   "a"    
+      `names(expected)`: "a" "b"
+      
+      `actual$a` is a double vector (1)
+      `expected$a` is a character vector ('b')
+      
+      `actual$b` is absent
+      `expected$b` is a double vector (10)
+
 # provide useful feedback on failure (2e)
 
     Code

tests/testthat/test-expect-equality.R

@@ -72,6 +72,10 @@ test_that("provide useful feedback on failure (3e)", {
   expect_snapshot_failure(expect_equal(x, "a"))
 })
 
+test_that("correctly spaces lines", {
+  expect_snapshot_failure(expect_equal(list(a = 1), list(a = "b", b = 10)))
+})
+
 test_that("provide useful feedback on failure (2e)", {
   local_edition(2)
   withr::local_options(testthat.edition_ignore = TRUE)
@@ -93,6 +97,7 @@ test_that("% is not treated as sprintf format specifier (#445)", {
   expect_success(expect_equal("%", "%"))
 })
 
+
 # 2nd edition ---------------------------------------------------
 
 test_that("useful message if objects equal but not identical", {