[LeverageLp]: Reduce the collateral by the same % as what the positio…

…n is reduced (#825)

* reduce same amount of collateral

* add test

x/leveragelp/keeper/position_close.go

@@ -27,6 +27,11 @@ func (k Keeper) ForceCloseLong(ctx sdk.Context, position types.Position, pool ty
 
 	repayAmount := debt.GetTotalLiablities().Mul(lpAmount).Quo(position.LeveragedLpAmount)
 
+	// Set collateral to same % as reduction in LP position
+	ratio := lpAmount.ToLegacyDec().Quo(position.LeveragedLpAmount.ToLegacyDec())
+	collateralLeft := position.Collateral.Amount.Sub(position.Collateral.Amount.ToLegacyDec().Mul(ratio).TruncateInt())
+	position.Collateral.Amount = collateralLeft
+
 	// Check if position has enough coins to repay else repay partial
 	bal := k.bankKeeper.GetBalance(ctx, position.GetPositionAddress(), position.Collateral.Denom)
 	userAmount := sdk.ZeroInt()

x/leveragelp/keeper/position_close_test.go

@@ -169,6 +169,10 @@ func (suite KeeperTestSuite) TestForceCloseLongPartial() {
 	repayAmountOut, err := k.ForceCloseLong(suite.ctx, *position, pool, position.LeveragedLpAmount.Quo(sdk.NewInt(2)), false)
 	suite.Require().NoError(err)
 	suite.Require().Equal(repayAmount.Quo(sdk.NewInt(2)).String(), repayAmountOut.String())
+
+	// Collateral should be reduced by 50%
+	after, _ := k.GetPosition(suite.ctx, addr, 1)
+	suite.Require().Equal(position.Collateral.Amount.Quo(sdk.NewInt(2)).String(), after.Collateral.Amount.String())
 }
 
 func (suite KeeperTestSuite) TestHealthDecreaseForInterest() {