test(iota-indexer): Add tests for CoinApi (#3580)

* feat(iota-indexer): Add tests for CoinApi

* Simplify `once_prepare_addr_with_iota_and_custom_coins`, reorder modules in main.rs

* Fixes after rebase

* Change return type of `once_prepare_addr_with_iota_and_custom_coins`

* Rename helper test functions

* Fix clippy

* Fix clippy

crates/iota-indexer/tests/data/dummy_modules_publish/Move.toml

@@ -0,0 +1,9 @@
+[package]
+name = "Examples"
+version = "0.0.1"
+
+[dependencies]
+Iota = { local = "../../../../iota-framework/packages/iota-framework" }
+
+[addresses]
+examples = "0x0"

crates/iota-indexer/tests/data/dummy_modules_publish/sources/trusted_coin.move

@@ -0,0 +1,40 @@
+// Copyright (c) Mysten Labs, Inc.
+// Modifications Copyright (c) 2024 IOTA Stiftung
+// SPDX-License-Identifier: Apache-2.0
+
+/// Example coin with a trusted owner responsible for minting/burning (e.g., a stablecoin)
+module examples::trusted_coin {
+    use std::option;
+    use iota::coin::{Self, TreasuryCap};
+    use iota::transfer;
+    use iota::tx_context::{Self, TxContext};
+
+    /// Name of the coin
+    struct TRUSTED_COIN has drop {}
+
+    /// Register the trusted currency to acquire its `TreasuryCap`. Because
+    /// this is a module initializer, it ensures the currency only gets
+    /// registered once.
+    fun init(witness: TRUSTED_COIN, ctx: &mut TxContext) {
+        // Get a treasury cap for the coin and give it to the transaction
+        // sender
+        let (treasury_cap, metadata) = coin::create_currency<TRUSTED_COIN>(witness, 2, b"TRUSTED", b"Trusted Coin", b"Trusted Coin for test", option::none(), ctx);
+        transfer::public_freeze_object(metadata);
+        transfer::public_transfer(treasury_cap, tx_context::sender(ctx))
+    }
+
+    public entry fun mint(treasury_cap: &mut TreasuryCap<TRUSTED_COIN>, amount: u64, ctx: &mut TxContext) {
+        let coin = coin::mint<TRUSTED_COIN>(treasury_cap, amount, ctx);
+        transfer::public_transfer(coin, tx_context::sender(ctx));
+    }
+
+    public entry fun transfer(treasury_cap: TreasuryCap<TRUSTED_COIN>, recipient: address) {
+        transfer::public_transfer(treasury_cap, recipient);
+    }
+
+    #[test_only]
+    /// Wrapper of module initializer for testing
+    public fun test_init(ctx: &mut TxContext) {
+        init(TRUSTED_COIN {}, ctx)
+    }
+}