tests: add Decimal serialization contract tests

jive-api/tests/contract_decimal_serialization.rs

@@ -0,0 +1,70 @@
+use chrono::{TimeZone, Utc};
+use rust_decimal::Decimal;
+use serde_json::Value;
+
+#[test]
+fn global_market_stats_decimal_serializes_as_string() {
+    use jive_money_api::models::global_market::GlobalMarketStats;
+
+    let stats = GlobalMarketStats {
+        total_market_cap_usd: Decimal::new(12_345_000_000, 0),
+        total_volume_24h_usd: Decimal::new(987_654_321, 0),
+        btc_dominance_percentage: Decimal::new(485, 1), // 48.5
+        eth_dominance_percentage: Some(Decimal::new(180, 1)), // 18.0
+        active_cryptocurrencies: 1000,
+        markets: Some(500),
+        updated_at: 1_700_000_000,
+    };
+
+    let val: Value = serde_json::to_value(&stats).expect("serialize market stats");
+    for key in [
+        "total_market_cap_usd",
+        "total_volume_24h_usd",
+        "btc_dominance_percentage",
+    ] {
+        assert!(val.get(key).and_then(|v| v.as_str()).is_some(), "{} should be string", key);
+    }
+    // updated_at is numeric unix timestamp
+    assert!(val.get("updated_at").and_then(|v| v.as_i64()).is_some());
+    assert!(val
+        .get("eth_dominance_percentage")
+        .and_then(|v| v.as_str())
+        .is_some());
+}
+
+#[test]
+fn account_response_decimal_serializes_as_string() {
+    use jive_money_api::handlers::accounts::AccountResponse;
+    use uuid::Uuid;
+
+    let resp = AccountResponse {
+        id: Uuid::nil(),
+        ledger_id: Uuid::nil(),
+        bank_id: None,
+        name: "Checking".to_string(),
+        account_type: "asset".to_string(),
+        account_number: None,
+        institution_name: None,
+        currency: "USD".to_string(),
+        current_balance: Decimal::new(12345, 2),
+        available_balance: Some(Decimal::new(12000, 2)),
+        credit_limit: None,
+        status: "active".to_string(),
+        is_manual: true,
+        color: None,
+        icon: None,
+        notes: None,
+        created_at: Utc.timestamp_opt(1_700_000_000, 0).unwrap(),
+        updated_at: Utc.timestamp_opt(1_700_000_000, 0).unwrap(),
+    };
+
+    let val: Value = serde_json::to_value(&resp).expect("serialize account response");
+    for key in ["current_balance"] {
+        assert!(val.get(key).and_then(|v| v.as_str()).is_some(), "{} should be string", key);
+    }
+    // Optional Decimal fields should also be strings when present
+    assert!(val
+        .get("available_balance")
+        .and_then(|v| v.as_str())
+        .is_some());
+}