feat: implement asset description storage and getter [#83]

contracts/price-oracle/src/lib.rs

@@ -248,6 +248,27 @@ impl PriceOracle {
         prices.keys()
     }
 
+    /// Store a human-readable description for an asset (e.g. "Nigerian Naira").
+    ///
+    /// Only the admin can call this.
+    pub fn set_asset_description(env: Env, admin: Address, asset: Symbol, description: soroban_sdk::String) {
+        admin.require_auth();
+        crate::auth::_require_authorized(&env, &admin);
+        env.storage()
+            .persistent()
+            .set(&DataKey::AssetDescription(asset), &description);
+    }
+
+    /// Get the human-readable description for an asset.
+    ///
+    /// Returns `Error::AssetNotFound` if no description has been set.
+    pub fn get_asset_description(env: Env, asset: Symbol) -> Result<soroban_sdk::String, Error> {
+        env.storage()
+            .persistent()
+            .get(&DataKey::AssetDescription(asset))
+            .ok_or(Error::AssetNotFound)
+    }
+
     /// Set the price data for a specific asset.
     ///
     /// # Arguments

contracts/price-oracle/src/test.rs

@@ -809,3 +809,85 @@ fn test_get_prices_empty_input_returns_empty_vec() {
 
     assert_eq!(results.len(), 0);
 }
+
+// ============================================================================
+// Asset Description Tests
+// ============================================================================
+
+#[test]
+fn test_set_and_get_asset_description() {
+    let env = Env::default();
+    env.mock_all_auths();
+
+    let contract_id = env.register(PriceOracle, ());
+    let client = PriceOracleClient::new(&env, &contract_id);
+    let admin = <soroban_sdk::Address as soroban_sdk::testutils::Address>::generate(&env);
+
+    env.as_contract(&contract_id, || {
+        crate::auth::_set_admin(&env, &soroban_sdk::vec![&env, admin.clone()]);
+    });
+
+    let asset = symbol_short!("NGN");
+    let description = soroban_sdk::String::from_str(&env, "Nigerian Naira");
+
+    client.set_asset_description(&admin, &asset, &description);
+
+    let result = client.get_asset_description(&asset);
+    assert_eq!(result, description);
+}
+
+#[test]
+fn test_get_asset_description_not_found_returns_error() {
+    let env = Env::default();
+    let contract_id = env.register(PriceOracle, ());
+    let client = PriceOracleClient::new(&env, &contract_id);
+
+    let result = client.try_get_asset_description(&symbol_short!("KES"));
+    match result {
+        Err(Ok(e)) => assert_eq!(e, Error::AssetNotFound),
+        other => panic!("expected AssetNotFound, got {:?}", other),
+    }
+}
+
+#[test]
+fn test_set_asset_description_non_admin_rejected() {
+    let env = Env::default();
+    env.mock_all_auths();
+
+    let contract_id = env.register(PriceOracle, ());
+    let client = PriceOracleClient::new(&env, &contract_id);
+    let admin = <soroban_sdk::Address as soroban_sdk::testutils::Address>::generate(&env);
+    let non_admin = <soroban_sdk::Address as soroban_sdk::testutils::Address>::generate(&env);
+
+    env.as_contract(&contract_id, || {
+        crate::auth::_set_admin(&env, &soroban_sdk::vec![&env, admin.clone()]);
+    });
+
+    let result = client.try_set_asset_description(
+        &non_admin,
+        &symbol_short!("NGN"),
+        &soroban_sdk::String::from_str(&env, "Nigerian Naira"),
+    );
+    assert!(result.is_err());
+}
+
+#[test]
+fn test_set_asset_description_can_be_updated() {
+    let env = Env::default();
+    env.mock_all_auths();
+
+    let contract_id = env.register(PriceOracle, ());
+    let client = PriceOracleClient::new(&env, &contract_id);
+    let admin = <soroban_sdk::Address as soroban_sdk::testutils::Address>::generate(&env);
+
+    env.as_contract(&contract_id, || {
+        crate::auth::_set_admin(&env, &soroban_sdk::vec![&env, admin.clone()]);
+    });
+
+    let asset = symbol_short!("GHS");
+    client.set_asset_description(&admin, &asset, &soroban_sdk::String::from_str(&env, "Ghanaian Cedi"));
+    client.set_asset_description(&admin, &asset, &soroban_sdk::String::from_str(&env, "Ghana Cedi"));
+
+    let result = client.get_asset_description(&asset);
+    assert_eq!(result, soroban_sdk::String::from_str(&env, "Ghana Cedi"));
+}

contracts/price-oracle/src/types.rs

@@ -1,11 +1,12 @@
-use soroban_sdk::{contracttype, Address};
+use soroban_sdk::{contracttype, Address, Symbol};
 
 /// Storage keys for contract data
 #[contracttype]
 pub enum DataKey {
     Admin,
     BaseCurrencyPairs,
     PriceData,
+    AssetDescription(Symbol),
 }
 
 /// Canonical storage format for a price entry.