diff --git a/src/lib.rs b/src/lib.rs
index 2179dc5..72c5a48 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -5,33 +5,14 @@ use std::os::raw::c_char;
 use tiktoken_rs;
 use tiktoken_rs::CoreBPE;
 
+mod utils;
+use utils::c_str_to_string;
+
 #[no_mangle]
 pub extern "C" fn tiktoken_init_logger() {
     SimpleLogger::new().init().unwrap();
 }
 
-fn get_string_from_c_char(ptr: *const c_char) -> Result<String, std::str::Utf8Error> {
-    let c_str = unsafe { CStr::from_ptr(ptr) };
-    let str_slice = c_str.to_str()?;
-    Ok(str_slice.to_string())
-}
-
-fn c_str_to_string(ptr: *const c_char) -> Option<String> {
-    if ptr.is_null() {
-        return None;
-    }
-
-    let c_str = match get_string_from_c_char(ptr) {
-        Ok(str) => str,
-        Err(_) => {
-            warn!("Invalid UTF-8 sequence provided!");
-            return None;
-        }
-    };
-
-    Some(c_str)
-}
-
 #[no_mangle]
 pub extern "C" fn tiktoken_r50k_base() -> *mut CoreBPE {
     let bpe = tiktoken_rs::r50k_base();
@@ -470,6 +451,7 @@ pub extern "C" fn tiktoken_c_version() -> *const c_char {
 mod tests {
     use super::*;
     use std::ffi::CString;
+    use utils::get_string_from_c_char;
 
     #[test]
     fn test_tiktoken_c_version() {
@@ -478,20 +460,6 @@ mod tests {
         assert_eq!(version, env!("CARGO_PKG_VERSION"));
     }
 
-    #[test]
-    fn test_get_string_from_c_char() {
-        let c_str = CString::new("I am a cat.").unwrap();
-        let str = get_string_from_c_char(c_str.as_ptr()).unwrap();
-        assert_eq!(str, "I am a cat.");
-    }
-
-    #[test]
-    fn test_c_str_to_string() {
-        let c_str = CString::new("I am a cat.").unwrap();
-        let str = c_str_to_string(c_str.as_ptr()).unwrap();
-        assert_eq!(str, "I am a cat.");
-    }
-
     #[test]
     fn test_c50k_base() {
         let corebpe = tiktoken_r50k_base();
diff --git a/src/utils.rs b/src/utils.rs
new file mode 100644
index 0000000..d41a910
--- /dev/null
+++ b/src/utils.rs
@@ -0,0 +1,45 @@
+use log::warn;
+use std::ffi::CStr;
+use std::os::raw::c_char;
+
+pub fn get_string_from_c_char(ptr: *const c_char) -> Result<String, std::str::Utf8Error> {
+    let c_str = unsafe { CStr::from_ptr(ptr) };
+    let str_slice = c_str.to_str()?;
+    Ok(str_slice.to_string())
+}
+
+pub fn c_str_to_string(ptr: *const c_char) -> Option<String> {
+    if ptr.is_null() {
+        return None;
+    }
+
+    let c_str = match get_string_from_c_char(ptr) {
+        Ok(str) => str,
+        Err(_) => {
+            warn!("Invalid UTF-8 sequence provided!");
+            return None;
+        }
+    };
+
+    Some(c_str)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::ffi::CString;
+
+    #[test]
+    fn test_get_string_from_c_char() {
+        let c_str = CString::new("I am a cat.").unwrap();
+        let str = get_string_from_c_char(c_str.as_ptr()).unwrap();
+        assert_eq!(str, "I am a cat.");
+    }
+
+    #[test]
+    fn test_c_str_to_string() {
+        let c_str = CString::new("I am a cat.").unwrap();
+        let str = c_str_to_string(c_str.as_ptr()).unwrap();
+        assert_eq!(str, "I am a cat.");
+    }
+}