Add tests for symmetric keys

Signed-off-by: Lee Smet <lee.smet@hotmail.com>

vault/src/key/symmetric.rs

@@ -8,6 +8,7 @@ use chacha20poly1305::{ChaCha20Poly1305, KeyInit, Nonce, aead::Aead};
 
 use crate::error::CryptoError;
 
+#[derive(Debug, PartialEq, Eq)]
 pub struct SymmetricKey([u8; 32]);
 
 /// Size of a nonce in ChaCha20Poly1305.
@@ -102,3 +103,49 @@ impl SymmetricKey {
         Self(key)
     }
 }
+
+#[cfg(test)]
+mod tests {
+
+    /// Using the same password derives the same key
+    #[test]
+    fn same_password_derives_same_key() {
+        const EXPECTED_KEY: [u8; 32] = [
+            4, 179, 233, 202, 225, 70, 211, 200, 7, 73, 115, 1, 85, 149, 90, 42, 160, 68, 16, 106,
+            136, 19, 197, 195, 153, 145, 179, 21, 37, 13, 37, 90,
+        ];
+        const PASSWORD: &str = "test123";
+
+        let key = super::SymmetricKey::derive_from_password(PASSWORD);
+
+        assert_eq!(key.0, EXPECTED_KEY);
+    }
+
+    /// Make sure an encrypted value with some key can be decrypted with the same key
+    #[test]
+    fn can_decrypt() {
+        let key = super::SymmetricKey::new();
+
+        let message = b"this is a message to decrypt";
+
+        let enc = key.encrypt(message).expect("Can encrypt message");
+        let dec = key.decrypt(&enc).expect("Can decrypt message");
+
+        assert_eq!(message.as_slice(), dec.as_slice());
+    }
+
+    /// Make sure a value encrypted with one key can't be decrypted with a different key. Since we
+    /// use AEAD encryption we will notice this when trying to decrypt
+    #[test]
+    fn different_key_cant_decrypt() {
+        let key1 = super::SymmetricKey::new();
+        let key2 = super::SymmetricKey::new();
+
+        let message = b"this is a message to decrypt";
+
+        let enc = key1.encrypt(message).expect("Can encrypt message");
+        let dec = key2.decrypt(&enc);
+
+        assert!(dec.is_err());
+    }
+}