add test for utils

Cargo.lock

@@ -337,6 +337,7 @@ name = "ethers-utils"
 version = "0.1.0"
 dependencies = [
  "ethereum-types 0.9.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-hex 2.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.110 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_json 1.0.53 (registry+https://github.com/rust-lang/crates.io-index)",
  "tiny-keccak 2.0.2 (registry+https://github.com/rust-lang/crates.io-index)",

crates/ethers-utils/Cargo.toml

@@ -9,3 +9,6 @@ ethereum-types = { version = "0.9.2", default-features = false, features = ["ser
 tiny-keccak = { version = "2.0.2", default-features = false }
 serde = { version = "1.0.110", default-features = false }
 serde_json = { version = "1.0.53", default-features = false, features = ["alloc"] }
+
+[dev-dependencies]
+rustc-hex = "2.1.0"

crates/ethers-utils/src/lib.rs

@@ -52,6 +52,16 @@ pub fn serialize<T: serde::Serialize>(t: &T) -> serde_json::Value {
 #[cfg(test)]
 mod tests {
     use super::*;
+    use rustc_hex::ToHex;
+
+    #[test]
+    // from https://emn178.github.io/online-tools/keccak_256.html
+    fn test_keccak256() {
+        assert_eq!(
+            keccak256("hello".as_bytes()).to_hex::<String>(),
+            "1c8aff950685c2ed4bc3174f3472287b56d9517b9c948127319a09a7a36deac8"
+        );
+    }
 
     // test vector taken from:
     // https://web3js.readthedocs.io/en/v1.2.2/web3-eth-accounts.html#hashmessage