When trying to use testthat::expect_equal() with two numbers and a tolerance argument, it passes when the arguments are in a certain order, but fails if the two numbers swap argument positions. I noticed that this function references using all.equal() from the base package, and that function also has the pass/fail difference when the arguments are swapped.
I expect the same answer regardless of the order of the first two arguments for both functions. Please let me know if this is not the right expectation.
library(testthat)
# expect_equal does not throw error with one pair of numbers to compare
expect_equal(5, 1, tolerance=1)
# But does when the two numbers are reversed in their arguments
tryCatch(expect_equal(1, 5, tolerance=1), expectation_failure=conditionMessage)
#> [1] "1 not equal to 5.\n1/1 mismatches\n[1] 1 - 5 == -4\n"
# Since this seems to reference `all.equal()` I tried there too, and see an issue:
all.equal(1, 5, tolerance=1)
#> [1] "Mean absolute difference: 4"
all.equal(5, 1, tolerance=1)
#> [1] TRUE
# My session info:
sessionInfo()
#> R version 3.3.3 (2017-03-06)
#> Platform: x86_64-w64-mingw32/x64 (64-bit)
#> Running under: Windows 7 x64 (build 7601) Service Pack 1
#>
#> locale:
#> [1] LC_COLLATE=English_United States.1252
#> [2] LC_CTYPE=English_United States.1252
#> [3] LC_MONETARY=English_United States.1252
#> [4] LC_NUMERIC=C
#> [5] LC_TIME=English_United States.1252
#>
#> attached base packages:
#> [1] stats graphics grDevices utils datasets methods base
#>
#> other attached packages:
#> [1] testthat_1.0.2
#>
#> loaded via a namespace (and not attached):
#> [1] backports_1.0.5 R6_2.2.1 magrittr_1.5 rprojroot_1.2
#> [5] tools_3.3.3 htmltools_0.3.6 yaml_2.1.14 crayon_1.3.2
#> [9] Rcpp_0.12.10 stringi_1.1.5 rmarkdown_1.5 knitr_1.15.1
#> [13] stringr_1.2.0 digest_0.6.12 evaluate_0.10