fix: correct outdated depositor.did (#84)

depositor/depositor.did

@@ -1,5 +1,5 @@
 type Account = record { owner : principal; subaccount : opt vec nat8 };
 type DepositArg = record { to : Account; memo : opt vec nat8; cycles : nat };
-type DepositResult = record { balance : nat; txid : nat };
+type DepositResult = record { balance : nat; block_index : nat };
 type InitArg = record { ledger_id : principal };
-service : (InitArg) -> { deposit : (DepositArg) -> (DepositResult) }
+service : (InitArg) -> { deposit : (DepositArg) -> (DepositResult) };

depositor/src/main.rs

@@ -42,3 +42,31 @@ async fn deposit(arg: DepositArg) -> DepositResult {
         .expect("Unable to call deposit");
     result
 }
+
+#[test]
+fn test_candid_interface_compatibility() {
+    use candid::utils::{service_equal, CandidSource};
+    use std::path::PathBuf;
+
+    candid::export_service!();
+    let exported_interface = __export_service();
+
+    let expected_interface =
+        PathBuf::from(std::env::var("CARGO_MANIFEST_DIR").unwrap()).join("depositor.did");
+
+    println!(
+        "Expected interface: {}\n\n",
+        CandidSource::File(expected_interface.as_path())
+            .load()
+            .unwrap()
+            .1
+            .unwrap()
+    );
+    println!("Exported interface: {}\n\n", exported_interface);
+
+    service_equal(
+        CandidSource::Text(&exported_interface),
+        CandidSource::File(expected_interface.as_path()),
+    )
+    .expect("The despositor interface is not compatible with the depositor.did file");
+}