Fixes #19

contracts/tokenization/StableDebtToken.sol

@@ -215,6 +215,9 @@ contract StableDebtToken is IStableDebtToken, DebtTokenBase {
     if (_amount == currentBalance) {
       usersData[_user].currentRate = 0;
       usersData[_user].lastUpdateTimestamp = 0;
+    } else {
+      //solium-disable-next-line
+      usersData[_user].lastUpdateTimestamp = uint40(block.timestamp);
     }
 
     if (balanceIncrease > _amount) {

test/helpers/scenarios/borrow-repay-stable.json

@@ -88,7 +88,41 @@
       ]
     },
     {
-      "description": "User 1 repays the DAI borrow after one year",
+      "description": "User 1 repays the half of the DAI borrow after one year",
+      "actions": [
+        {
+          "name": "mint",
+          "description": "Mint 10 DAI to cover the interest",
+          "args": {
+            "reserve": "DAI",
+            "amount": "10",
+            "user": "1"
+          },
+          "expected": "success"
+        },
+        {
+          "name": "approve",
+          "args": {
+            "reserve": "DAI",
+            "user": "1"
+          },
+          "expected": "success"
+        },
+        {
+          "name": "repay",
+          "args": {
+            "reserve": "DAI",
+            "amount": "50",
+            "user": "1",
+            "onBehalfOf": "1",
+            "borrowRateMode": "stable"
+          },
+          "expected": "success"
+        }
+      ]
+    },
+    {
+      "description": "User 1 repays the rest of the DAI borrow after one year",
       "actions": [
         {
           "name": "mint",

test/helpers/utils/calculations.ts

@@ -658,6 +658,10 @@ export const calcExpectedUserDataAfterRepay = (
         '0'
       );
     }
+    else{
+      expectedUserData.stableBorrowRate = userDataBeforeAction.stableBorrowRate;
+      expectedUserData.stableRateLastUpdated = txTimestamp;
+    }
   } else {
     expectedUserData.currentStableDebt = stableBorrowBalance;
     expectedUserData.principalStableDebt = userDataBeforeAction.principalStableDebt;