diff --git a/tests/expectations/rename_case.c b/tests/expectations/rename_case.c
index c574823..0276456 100644
--- a/tests/expectations/rename_case.c
+++ b/tests/expectations/rename_case.c
@@ -12,3 +12,5 @@ void test_snake_case(int32_t foo_bar);
 void test_screaming_snake_case(int32_t FOO_BAR);
 
 void test_gecko_case(int32_t aFooBar);
+
+void test_prefix(int32_t prefix_foo_bar);
diff --git a/tests/expectations/rename_case.compat.c b/tests/expectations/rename_case.compat.c
index 1d2cb1c..ba66eee 100644
--- a/tests/expectations/rename_case.compat.c
+++ b/tests/expectations/rename_case.compat.c
@@ -17,6 +17,8 @@ void test_screaming_snake_case(int32_t FOO_BAR);
 
 void test_gecko_case(int32_t aFooBar);
 
+void test_prefix(int32_t prefix_foo_bar);
+
 #ifdef __cplusplus
 }  // extern "C"
 #endif  // __cplusplus
diff --git a/tests/expectations/rename_case.cpp b/tests/expectations/rename_case.cpp
index 0d5a6d9..c87cfbf 100644
--- a/tests/expectations/rename_case.cpp
+++ b/tests/expectations/rename_case.cpp
@@ -16,4 +16,6 @@ void test_screaming_snake_case(int32_t FOO_BAR);
 
 void test_gecko_case(int32_t aFooBar);
 
+void test_prefix(int32_t prefix_foo_bar);
+
 }  // extern "C"
diff --git a/tests/expectations/rename_case.pyx b/tests/expectations/rename_case.pyx
index 5fd35fc..a781782 100644
--- a/tests/expectations/rename_case.pyx
+++ b/tests/expectations/rename_case.pyx
@@ -15,3 +15,5 @@ cdef extern from *:
   void test_screaming_snake_case(int32_t FOO_BAR);
 
   void test_gecko_case(int32_t aFooBar);
+
+  void test_prefix(int32_t prefix_foo_bar);
diff --git a/tests/rust/rename_case.rs b/tests/rust/rename_case.rs
index e83227d..d01b71e 100644
--- a/tests/rust/rename_case.rs
+++ b/tests/rust/rename_case.rs
@@ -17,3 +17,7 @@ pub extern "C" fn test_screaming_snake_case(foo_bar: i32) {}
 /// cbindgen:rename-all=GeckoCase
 #[no_mangle]
 pub extern "C" fn test_gecko_case(foo_bar: i32) {}
+
+/// cbindgen:rename-all=prefix:prefix_
+#[no_mangle]
+pub extern "C" fn test_prefix(foo_bar: i32) {}