diff --git a/src/main.rs b/src/main.rs
index cece234..4e27fde 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -24,6 +24,9 @@ lazy_static::lazy_static! {
     pub static ref ROUTE_REGISTRY: Mutex<Vec<Box<dyn WithState>>> = Mutex::new(Vec::new());
 }
 
+#[cfg(test)]
+mod tests;
+
 #[tokio::main]
 async fn main() {
     let conf = config::load();
diff --git a/tests/endpoints.rs b/src/tests/endpoints.rs
similarity index 100%
rename from tests/endpoints.rs
rename to src/tests/endpoints.rs
diff --git a/src/tests/mod.rs b/src/tests/mod.rs
new file mode 100644
index 0000000..518b2d7
--- /dev/null
+++ b/src/tests/mod.rs
@@ -0,0 +1,2 @@
+mod utils;
+mod endpoints;
diff --git a/src/tests/utils.rs b/src/tests/utils.rs
new file mode 100644
index 0000000..486900e
--- /dev/null
+++ b/src/tests/utils.rs
@@ -0,0 +1,37 @@
+#[cfg(test)]
+pub mod tests {
+    use crate::utils::{to_hex, to_hex_trimmed};
+    use starknet::core::types::FieldElement;
+    #[test]
+    fn test_to_hex() {
+        let zero = FieldElement::ZERO;
+        assert_eq!(
+            to_hex(zero),
+            "0x0000000000000000000000000000000000000000000000000000000000000000"
+        );
+
+        let small = FieldElement::from(42u64);
+        assert_eq!(
+            to_hex(small),
+            "0x000000000000000000000000000000000000000000000000000000000000002a"
+        );
+
+        let large = FieldElement::from_hex_be("0x123456789abcdef0").unwrap();
+        assert_eq!(
+            to_hex(large),
+            "0x000000000000000000000000000000000000000000000000123456789abcdef0"
+        );
+    }
+
+    #[test]
+    fn test_to_hex_trimmed() {
+        let zero = FieldElement::ZERO;
+        assert_eq!(to_hex_trimmed(zero), "0x0");
+
+        let small = FieldElement::from(42u64);
+        assert_eq!(to_hex_trimmed(small), "0x2a");
+
+        let large = FieldElement::from_hex_be("0x123456789abcdef0").unwrap();
+        assert_eq!(to_hex_trimmed(large), "0x123456789abcdef0");
+    }
+}