From 02f19c9baafd5019d7abaea1a9896c8586604d91 Mon Sep 17 00:00:00 2001
From: eau leaf <eau.leaf@gmail.com>
Date: Tue, 6 Jun 2023 23:04:45 -0700
Subject: [PATCH 1/2] cosmetic

---
 R/trunc.R                   | 10 ++++++++--
 tests/testthat/test-trunc.R |  9 +++++++++
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/R/trunc.R b/R/trunc.R
index b48c78bf..d9366612 100644
--- a/R/trunc.R
+++ b/R/trunc.R
@@ -30,15 +30,21 @@ str_trunc <- function(string, width, side = c("right", "left", "center"),
     cli::cli_abort(
       "`width` ({width}) is shorter than `ellipsis` ({str_length(ellipsis)})."
     )
+  } else if (width... > 1) {
+    end_c <- end_l <- -1
+  } else if (width... == 1) {
+    end_c <- 0; end_l <- -1
+  } else {
+    end_c <- end_l <- 0
   }
 
   string[too_long] <- switch(side,
     right  = str_c(str_sub(string[too_long], 1, width...), ellipsis),
-    left   = str_c(ellipsis, str_sub(string[too_long], -width..., -1)),
+    left   = str_c(ellipsis, str_sub(string[too_long], -width..., end_l)),
     center = str_c(
         str_sub(string[too_long], 1, ceiling(width... / 2)),
         ellipsis,
-        str_sub(string[too_long], -floor(width... / 2), -1)
+        str_sub(string[too_long], -floor(width... / 2), end_c)
       )
   )
   string
diff --git a/tests/testthat/test-trunc.R b/tests/testthat/test-trunc.R
index 1bb80614..d195dfa1 100644
--- a/tests/testthat/test-trunc.R
+++ b/tests/testthat/test-trunc.R
@@ -35,3 +35,12 @@ test_that("does not truncate to a length shorter than elipsis", {
     str_trunc("foobar", 3, ellipsis = "....")
   })
 })
+
+test_that("right side of ellipsis correctly substrings when internal var `width...` is 0 or 1", {
+  expect_equal(str_trunc(c('', 'a', 'aa', 'aaa', 'aaaa','aaaaa'), width = 3, "center", ".."),
+               c('', 'a', 'aa', 'aaa', 'a..','a..'))
+  expect_equal(str_trunc(c('', 'a', 'aa', 'aaa', 'aaaa','aaaaa'), width = 2, "left", ".."),
+               c('', 'a', 'aa', '..', '..','..'))
+})
+
+

From d27b68f37e8b67fd3324e97cc06a0041c9af010d Mon Sep 17 00:00:00 2001
From: eauleaf <81445509+eauleaf@users.noreply.github.com>
Date: Wed, 7 Jun 2023 10:55:26 -0700
Subject: [PATCH 2/2] Update test-trunc.R

added a couple more tests for completeness
---
 tests/testthat/test-trunc.R | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/tests/testthat/test-trunc.R b/tests/testthat/test-trunc.R
index d195dfa1..8fc1919e 100644
--- a/tests/testthat/test-trunc.R
+++ b/tests/testthat/test-trunc.R
@@ -37,10 +37,12 @@ test_that("does not truncate to a length shorter than elipsis", {
 })
 
 test_that("right side of ellipsis correctly substrings when internal var `width...` is 0 or 1", {
-  expect_equal(str_trunc(c('', 'a', 'aa', 'aaa', 'aaaa','aaaaa'), width = 3, "center", ".."),
-               c('', 'a', 'aa', 'aaa', 'a..','a..'))
-  expect_equal(str_trunc(c('', 'a', 'aa', 'aaa', 'aaaa','aaaaa'), width = 2, "left", ".."),
-               c('', 'a', 'aa', '..', '..','..'))
+  expect_equal(str_trunc(c('', 'a', 'aa', 'aaa', 'aaaa','aaaaa'), width = 3, "center", ".."), c('', 'a', 'aa', 'aaa', 'a..','a..')) # width... == 1
+  expect_equal(str_trunc(c('', 'a', 'aa', 'aaa', 'aaaa','aaaaa'), width = 3, "left", ".."), c('', 'a', 'aa', 'aaa', '..a','..a')) # width... == 1
+  expect_equal(str_trunc(c('', 'a', 'aa', 'aaa', 'aaaa','aaaaa'), width = 2, "center", ".."), c('', 'a', 'aa', '..', '..','..')) # width... == 0
+  expect_equal(str_trunc(c('', 'a', 'aa', 'aaa', 'aaaa','aaaaa'), width = 2, "left", ".."), c('', 'a', 'aa', '..', '..','..')) # width... == 0
+  expect_equal(str_trunc(c('', 'a', 'aa', 'aaa', 'aaaa','aaaaa'), width = 1, "center", ""), c('', 'a', 'a', 'a', 'a','a')) # width... == 1, empty ellipsis
+  expect_equal(str_trunc(c('', 'a', 'aa', 'aaa', 'aaaa','aaaaa'), width = 1, "left", ""), c('', 'a', 'a', 'a', 'a','a')) # width... == 1, empty ellipsis
 })