diff --git a/crates/typos-cli/tests/cmd/extend-words-case.in/_typos.toml b/crates/typos-cli/tests/cmd/extend-words-case.in/_typos.toml
new file mode 100644
index 0000000..97a66db
--- /dev/null
+++ b/crates/typos-cli/tests/cmd/extend-words-case.in/_typos.toml
@@ -0,0 +1,2 @@
+[default.extend-words]
+"trailling" = "trailing"
diff --git a/crates/typos-cli/tests/cmd/extend-words-case.in/file.txt b/crates/typos-cli/tests/cmd/extend-words-case.in/file.txt
new file mode 100644
index 0000000..5a479ac
--- /dev/null
+++ b/crates/typos-cli/tests/cmd/extend-words-case.in/file.txt
@@ -0,0 +1 @@
+public function noErrorOnTraillingSemicolonAndWhitespace(Connection $connection)
diff --git a/crates/typos-cli/tests/cmd/extend-words-case.toml b/crates/typos-cli/tests/cmd/extend-words-case.toml
new file mode 100644
index 0000000..cef3b95
--- /dev/null
+++ b/crates/typos-cli/tests/cmd/extend-words-case.toml
@@ -0,0 +1,13 @@
+bin.name = "typos"
+args = ""
+status.code = 2
+stdin = ""
+stdout = """
+error: `Trailling` should be `trailing`
+  --> ./file.txt:1:26
+  |
+1 | public function noErrorOnTraillingSemicolonAndWhitespace(Connection $connection)
+  |                          ^^^^^^^^^
+  |
+"""
+stderr = ""