From cd01845ff2eed74ad56afb6f2f78cfb3ab337894 Mon Sep 17 00:00:00 2001
From: Alexandre ABRIOUX <alexandre-abrioux@users.noreply.github.com>
Date: Wed, 3 Mar 2021 16:37:11 +0100
Subject: [PATCH] add failing test case

---
 .../v2/computation-and-formatting.test.ts     | 23 +++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/src/test/v2/computation-and-formatting.test.ts b/src/test/v2/computation-and-formatting.test.ts
index c10a76ae..7317ed72 100644
--- a/src/test/v2/computation-and-formatting.test.ts
+++ b/src/test/v2/computation-and-formatting.test.ts
@@ -4,6 +4,7 @@ import {
   formatUserSummaryData,
 } from '../../v2/computations-and-formatting';
 import BigNumber from 'bignumber.js';
+import { getCompoundedBalance } from '../../helpers/pool-math';
 
 const mockReserve: ReserveData = {
   underlyingAsset: '0xff795577d9ac8bd7d90ee22b6c1703490b6512fd',
@@ -151,5 +152,27 @@ describe('computations and formattings', () => {
 
       expect(new BigNumber(second.totalDebt).gte(first.totalDebt)).toBe(true);
     });
+
+    it('should compute collateral balance from blockchain data', () => {
+      // data exported from user 0xa5a69107816c5e3dfa5561e6b621dfe6294f6e5b
+      // at block number: 11581421
+      // reserve: YFI
+      const scaledATokenBalance = '161316503206059870';
+      const liquidityIndex = '1001723339432542553527150680';
+      const currentLiquidityRate = '22461916953455574582370088';
+      const lastUpdateTimestamp = 1609673617;
+      // at a later time, but on the same block
+      // expected balance computed with hardhat
+      const currentTimestamp = 1609675535;
+      const expectedATokenBalance = '161594727054623229';
+      const underlyingBalance = getCompoundedBalance(
+        scaledATokenBalance,
+        liquidityIndex,
+        currentLiquidityRate,
+        lastUpdateTimestamp,
+        currentTimestamp
+      ).toString();
+      expect(underlyingBalance).toBe(expectedATokenBalance);
+    });
   });
 });