diff --git a/tests/testthat/test-remove.R b/tests/testthat/test-remove.R
index f8ea1b7c..c178a236 100644
--- a/tests/testthat/test-remove.R
+++ b/tests/testthat/test-remove.R
@@ -7,3 +7,30 @@ test_that("str_remove() preserves names", {
   x <- c(C = "3", B = "2", A = "1")
   expect_equal(names(str_remove(x, "[0-9]")), names(x))
 })
+
+test_that("NA values pass through unchanged", {
+  expect_equal(str_remove(NA, "a"), NA_character_)
+  expect_equal(str_remove_all(NA, "a"), NA_character_)
+  expect_equal(str_remove(c(NA, "abc"), "b"), c(NA, "ac"))
+  expect_equal(str_remove_all(c(NA, "ababa"), "ba"), c(NA, "a"))
+})
+
+test_that("empty strings pass through unchanged", {
+  expect_equal(str_remove("", "a"), "")
+  expect_equal(str_remove_all("", "a"), "")
+})
+
+test_that("zero-length input returns zero-length output", {
+  expect_equal(str_remove(character(), "a"), character())
+  expect_equal(str_remove_all(character(), "a"), character())
+})
+
+test_that("factor input is handled correctly", {
+  expect_equal(str_remove(factor("abc"), "b"), "ac")
+  expect_equal(str_remove_all(factor("ababa"), "ba"), "a")
+})
+
+test_that("no match returns string unchanged", {
+  expect_equal(str_remove("abc", "z"), "abc")
+  expect_equal(str_remove_all("abc", "z"), "abc")
+})