test: add shared multi-user contract harness

contracts/locked_in/Cargo.toml

@@ -21,3 +21,4 @@ soroban-sdk = "23.0.3"
 stellar-xdr = { version = "23.0.0", features = ["curr", "serde"] }
 soroban-sdk = { version = "23.0.3", features = ["testutils"] }
 mock_pool = { path = "../mock_pool" }
+test_utils = { path = "../test_utils" }

contracts/locked_in/src/test.rs

@@ -5,6 +5,7 @@ use super::*;
 use mock_pool::{MockPool, MockPoolClient};
 use soroban_sdk::testutils::{Address as _, Ledger};
 use soroban_sdk::{token::StellarAssetClient, Env};
+use test_utils::{create_token_contract, mint_tokens};
 
 const ONE_YEAR: u64 = 31_536_000;
 
@@ -29,11 +30,8 @@ fn setup() -> (Env, Address, Address, Address, LockedInClient<'static>) {
     let admin = Address::generate(&env);
     let user = Address::generate(&env);
 
-    let issuer = Address::generate(&env);
-    let asset = env.register_stellar_asset_contract_v2(issuer);
-    let token_addr = asset.address();
-    let token_admin = StellarAssetClient::new(&env, &token_addr);
-    token_admin.mint(&user, &10_000_000_000_i128); // 1000 USDC
+    let (token_addr, token) = create_token_contract(&env, &admin);
+    mint_tokens(&env, &token, &user, 10_000_000_000_i128); // 1000 USDC
 
     let contract_id = env.register(LockedIn, (admin.clone(), token_addr.clone()));
     let client = LockedInClient::new(&env, &contract_id);

contracts/mock_pool/Cargo.toml

@@ -20,3 +20,4 @@ soroban-sdk = "23.0.3"
 [dev-dependencies]
 stellar-xdr = { version = "23.0.0", features = ["curr", "serde"] }
 soroban-sdk = { version = "23.0.3", features = ["testutils"] }
+test_utils = { path = "../test_utils" }

contracts/mock_pool/src/test.rs

@@ -3,7 +3,8 @@ extern crate std;
 
 use super::*;
 use soroban_sdk::testutils::{Address as _, Ledger};
-use soroban_sdk::{token::StellarAssetClient, Env};
+use soroban_sdk::Env;
+use test_utils::{assert_solvable, create_token_contract, mint_tokens};
 
 const SECONDS_PER_YEAR_U64: u64 = 31_536_000;
 
@@ -15,12 +16,9 @@ fn setup() -> (Env, Address, Address, Address, MockPoolClient<'static>) {
     let admin = Address::generate(&env);
     let supplier = Address::generate(&env);
 
-    let issuer = Address::generate(&env);
-    let asset = env.register_stellar_asset_contract_v2(issuer.clone());
-    let token_addr = asset.address();
-    let token_admin = StellarAssetClient::new(&env, &token_addr);
-    token_admin.mint(&supplier, &10_000_000_000_i128); // 1000 USDC (7 decimals)
-    token_admin.mint(&admin, &10_000_000_000_i128); // 1000 USDC for the reserve
+    let (token_addr, token) = create_token_contract(&env, &admin);
+    mint_tokens(&env, &token, &supplier, 10_000_000_000_i128); // 1000 USDC (7 decimals)
+    mint_tokens(&env, &token, &admin, 10_000_000_000_i128); // 1000 USDC for the reserve
 
     // 10% APY (1000 bps)
     let contract_id = env.register(MockPool, (admin.clone(), token_addr.clone(), 1000u32));
@@ -37,6 +35,19 @@ fn test_supply_records_principal() {
     assert_eq!(client.get_position(&supplier), 1_000_000_000); // no time elapsed yet
 }
 
+#[test]
+fn test_multiple_users_remain_solvable() {
+    let (env, _admin, supplier, token_addr, client) = setup();
+    let second = Address::generate(&env);
+    let token = soroban_sdk::token::TokenClient::new(&env, &token_addr);
+    mint_tokens(&env, &token, &second, 1_000_000_000);
+
+    client.supply(&supplier, &1_000_000_000);
+    client.supply(&second, &1_000_000_000);
+
+    assert_solvable(&env, &token_addr, &client.address, 2_000_000_000);
+}
+
 #[test]
 fn test_yield_accrues_linearly() {
     let (env, _admin, supplier, _t, client) = setup();

contracts/plans/Cargo.toml

@@ -20,3 +20,4 @@ soroban-sdk = "23.0.3"
 [dev-dependencies]
 stellar-xdr = { version = "23.0.0", features = ["curr", "serde"] }
 soroban-sdk = { version = "23.0.3", features = ["testutils"] }
+test_utils = { path = "../test_utils" }

contracts/plans/src/test.rs

@@ -1,19 +1,9 @@
 #![cfg(test)]
+extern crate std;
 
 use super::*;
-use soroban_sdk::{
-    testutils::{Address as _, Ledger, LedgerInfo},
-    token::{StellarAssetClient, TokenClient},
-    Address, Env, String, Vec,
-};
-
-// Test token setup helper
-fn create_token_contract<'a>(env: &Env, admin: &Address) -> (Address, TokenClient<'a>) {
-    let stellar_asset = env.register_stellar_asset_contract_v2(admin.clone());
-    let token_address = stellar_asset.address();
-    let token = TokenClient::new(env, &token_address);
-    (token_address, token)
-}
+use soroban_sdk::{testutils::Address as _, Address, Env, String, Vec};
+use test_utils::{create_token_contract, mint_tokens, set_ledger_time};
 
 // Contract setup helper
 fn create_plans_contract<'a>(
@@ -26,25 +16,6 @@ fn create_plans_contract<'a>(
     client
 }
 
-// Helper to mint tokens to a user
-fn mint_tokens(env: &Env, token: &TokenClient, to: &Address, amount: i128) {
-    let stellar_asset = StellarAssetClient::new(env, &token.address);
-    stellar_asset.mint(to, &amount);
-}
-
-// Helper to set ledger time
-fn set_ledger_time(env: &Env, timestamp: u64, sequence: u32) {
-    env.ledger().set(LedgerInfo {
-        timestamp,
-        protocol_version: 23,
-        sequence_number: sequence,
-        network_id: Default::default(),
-        base_reserve: 10,
-        min_temp_entry_ttl: 10,
-        min_persistent_entry_ttl: 10,
-        max_entry_ttl: 3110400,
-    });
-}
 
 #[test]
 fn test_initialization() {
@@ -782,4 +753,4 @@ fn test_recurring_bill_with_recurrence_calendar() {
     let bill = client.get_bill(&bill_id);
     assert_eq!(bill.is_recurring, true);
     assert_eq!(bill.recurrence_calendar.len(), 3);
-}
+}

contracts/spend_save/Cargo.toml

@@ -20,3 +20,4 @@ soroban-sdk = "23.0.3"
 [dev-dependencies]
 stellar-xdr = { version = "23.0.0", features = ["curr", "serde"] }
 soroban-sdk = { version = "23.0.3", features = ["testutils"] }
+test_utils = { path = "../test_utils" }

contracts/spend_save/src/test.rs

@@ -3,7 +3,8 @@ extern crate std;
 
 use super::*;
 use soroban_sdk::testutils::{Address as _, Ledger};
-use soroban_sdk::{token::StellarAssetClient, Env};
+use soroban_sdk::Env;
+use test_utils::{create_token_contract, mint_tokens};
 
 const SECONDS_PER_DAY: u64 = 86_400;
 
@@ -19,11 +20,8 @@ fn setup_at(ts: u64) -> (Env, Address, Address, Address, SpendSaveClient<'static
 
     let admin = Address::generate(&env);
     let user = Address::generate(&env);
-    let issuer = Address::generate(&env);
-    let asset = env.register_stellar_asset_contract_v2(issuer);
-    let token_addr = asset.address();
-    let token_admin = StellarAssetClient::new(&env, &token_addr);
-    token_admin.mint(&user, &10_000_000_000_i128); // 1000 USDC
+    let (token_addr, token) = create_token_contract(&env, &admin);
+    mint_tokens(&env, &token, &user, 10_000_000_000_i128); // 1000 USDC
 
     let contract_id = env.register(SpendSave, (admin.clone(), token_addr.clone()));
     let client = SpendSaveClient::new(&env, &contract_id);

contracts/target_savings/Cargo.toml

@@ -21,3 +21,4 @@ soroban-sdk = "23.0.3"
 stellar-xdr = { version = "23.0.0", features = ["curr", "serde"] }
 soroban-sdk = { version = "23.0.3", features = ["testutils"] }
 mock_pool = { path = "../mock_pool" }
+test_utils = { path = "../test_utils" }

contracts/target_savings/src/test.rs

@@ -5,6 +5,7 @@ use super::*;
 use mock_pool::{MockPool, MockPoolClient};
 use soroban_sdk::testutils::{Address as _, Ledger};
 use soroban_sdk::{token::StellarAssetClient, Env, String};
+use test_utils::{create_token_contract, mint_tokens};
 
 const PERIOD_WEEK: u64 = 604_800;
 const ONE_YEAR: u64 = 31_536_000;
@@ -31,13 +32,8 @@ fn setup() -> (Env, Address, Address, Address, TargetSavingsClient<'static>) {
     let user = Address::generate(&env);
 
     // Stellar Asset Contract for the test token
-    let issuer = Address::generate(&env);
-    let asset = env.register_stellar_asset_contract_v2(issuer.clone());
-    let token_addr = asset.address();
-    let token_admin = StellarAssetClient::new(&env, &token_addr);
-
-    // Mint some USDC to the user
-    token_admin.mint(&user, &10_000_000_000_i128); // 1000 USDC (7 decimals)
+    let (token_addr, token) = create_token_contract(&env, &admin);
+    mint_tokens(&env, &token, &user, 10_000_000_000_i128); // 1000 USDC (7 decimals)
 
     let contract_id = env.register(TargetSavings, (admin.clone(), token_addr.clone()));
     let client = TargetSavingsClient::new(&env, &contract_id);

contracts/test_utils/Cargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "test_utils"
+version.workspace = true
+edition.workspace = true
+license.workspace = true
+repository.workspace = true
+publish = false
+
+[dependencies]
+soroban-sdk = { version = "23.0.3", features = ["testutils"] }

contracts/test_utils/src/lib.rs

@@ -0,0 +1,52 @@
+use soroban_sdk::{
+    testutils::{Address as _, Ledger, LedgerInfo},
+    token::{StellarAssetClient, TokenClient},
+    Address, Env, Vec,
+};
+
+pub fn create_token_contract<'a>(env: &'a Env, admin: &Address) -> (Address, TokenClient<'a>) {
+    let asset = env.register_stellar_asset_contract_v2(admin.clone());
+    let address = asset.address();
+    (address.clone(), TokenClient::new(env, &address))
+}
+
+pub fn create_funded_users(
+    env: &Env,
+    token: &TokenClient,
+    count: u32,
+    amount: i128,
+) -> Vec<Address> {
+    let issuer = StellarAssetClient::new(env, &token.address);
+    let mut users = Vec::new(env);
+    for _ in 0..count {
+        let user = Address::generate(env);
+        issuer.mint(&user, &amount);
+        users.push_back(user);
+    }
+    users
+}
+
+pub fn mint_tokens(env: &Env, token: &TokenClient, to: &Address, amount: i128) {
+    StellarAssetClient::new(env, &token.address).mint(to, &amount);
+}
+
+pub fn set_ledger_time(env: &Env, timestamp: u64, sequence: u32) {
+    env.ledger().set(LedgerInfo {
+        timestamp,
+        protocol_version: 23,
+        sequence_number: sequence,
+        network_id: Default::default(),
+        base_reserve: 10,
+        min_temp_entry_ttl: 10,
+        min_persistent_entry_ttl: 10,
+        max_entry_ttl: 3_110_400,
+    });
+}
+
+pub fn assert_solvable(env: &Env, token_address: &Address, contract: &Address, total_owed: i128) {
+    let token = TokenClient::new(env, token_address);
+    assert!(
+        token.balance(contract) >= total_owed,
+        "contract token balance is below the sum of outstanding claims"
+    );
+}