test(eco-token): add unit test asserting BurnEvent topic indexed from address schema (#85)

CHANGELOG.md

@@ -32,6 +32,9 @@ package version is bumped.
 
 #### `eco-token`
 
+- **[#85] Index `from` address in `BurnEvent` topic schema.**
+  `BurnEvent.from` is marked `#[topic]`, ensuring on-chain burn history can be filtered by address, matching the topic indexing conventions of `TransferEvent`, `MintEvent`, and `ApproveEvent`. Added `test_burn_emits_event_with_indexed_from` verifying topic vector layout and payload schema.
+
 - **[#67] Prevent self-transfer allowance drain in `transfer_from` and fix storage re-fetch TOCTOU in `spend_allowance`.**
   `transfer_from` now panics with `"token: cannot transfer to self"` when `from == to`, preventing spenders from burning an owner's allowance without transferring tokens. `spend_allowance` in `storage.rs` now accepts the `&Allowance` struct directly instead of re-fetching from persistent storage with `.unwrap()`, eliminating a potential TOCTOU window.
 

contracts/eco-token/src/token.rs

@@ -1142,6 +1142,46 @@ mod test {
         assert_eq!(client.total_supply(), 600);
     }
 
+    #[test]
+    fn test_burn_emits_event_with_indexed_from() {
+        use soroban_sdk::testutils::Events as _;
+        use soroban_sdk::vec;
+        use soroban_sdk::{IntoVal, Symbol, Val};
+        let e = Env::default();
+        let admin = Address::generate(&e);
+        let user = Address::generate(&e);
+        let contract_id = e.register(TokenContract, ());
+        let client = TokenContractClient::new(&e, &contract_id);
+
+        client.initialize(
+            &admin,
+            &String::from_str(&e, "ECO"),
+            &String::from_str(&e, "ECO"),
+            &7,
+        );
+
+        e.mock_all_auths();
+        client.mint(&user, &1000);
+        client.burn(&user, &400);
+
+        let events = e.events().all();
+        let expected_topics: soroban_sdk::Vec<Val> = vec![
+            &e,
+            Symbol::new(&e, "burn_event").to_val(),
+            user.clone().into_val(&e),
+        ];
+        let expected_data: Val = soroban_sdk::Map::<Symbol, Val>::from_array(
+            &e,
+            [(Symbol::new(&e, "amount"), 400i128.into_val(&e))],
+        )
+        .into_val(&e);
+
+        assert_eq!(
+            events,
+            vec![&e, (contract_id, expected_topics, expected_data)]
+        );
+    }
+
     #[test]
     #[should_panic(expected = "token: insufficient balance")]
     fn test_burn_more_than_balance() {