Hard: delete borrow/deposit from store on 0 amount (#766)

* delete borrow/deposit on 0 balance

* add/update tests to ensure deletion

* delete from LTV index

x/hard/keeper/liquidation.go

@@ -268,6 +268,10 @@ func (k Keeper) IsWithinValidLtvRange(ctx sdk.Context, deposit types.Deposit, bo
 // UpdateBorrowAndLtvIndex updates a borrow and its LTV index value in the store
 func (k Keeper) UpdateBorrowAndLtvIndex(ctx sdk.Context, borrow types.Borrow, newLtv, oldLtv sdk.Dec) {
 	k.RemoveFromLtvIndex(ctx, oldLtv, borrow.Borrower)
+	if borrow.Amount.Empty() {
+		k.DeleteBorrow(ctx, borrow)
+		return
+	}
 	k.SetBorrow(ctx, borrow)
 	k.InsertIntoLtvIndex(ctx, newLtv, borrow.Borrower)
 }
@@ -275,6 +279,10 @@ func (k Keeper) UpdateBorrowAndLtvIndex(ctx sdk.Context, borrow types.Borrow, ne
 // UpdateDepositAndLtvIndex updates a deposit and its LTV index value in the store
 func (k Keeper) UpdateDepositAndLtvIndex(ctx sdk.Context, deposit types.Deposit, newLtv, oldLtv sdk.Dec) {
 	k.RemoveFromLtvIndex(ctx, oldLtv, deposit.Depositor)
+	if deposit.Amount.Empty() {
+		k.DeleteDeposit(ctx, deposit)
+		return
+	}
 	k.SetDeposit(ctx, deposit)
 	k.InsertIntoLtvIndex(ctx, newLtv, deposit.Depositor)
 }

x/hard/keeper/repay_test.go

@@ -29,6 +29,7 @@ func (suite *KeeperTestSuite) TestRepay() {
 
 	type errArgs struct {
 		expectPass   bool
+		expectDelete bool
 		contains     string
 	}
 
@@ -53,6 +54,7 @@ func (suite *KeeperTestSuite) TestRepay() {
 			},
 			errArgs{
 				expectPass:   true,
+				expectDelete: false,
 				contains:     "",
 			},
 		},
@@ -68,6 +70,7 @@ func (suite *KeeperTestSuite) TestRepay() {
 			},
 			errArgs{
 				expectPass:   true,
+				expectDelete: true,
 				contains:     "",
 			},
 		},
@@ -83,6 +86,7 @@ func (suite *KeeperTestSuite) TestRepay() {
 			},
 			errArgs{
 				expectPass:   true,
+				expectDelete: true,
 				contains:     "",
 			},
 		},
@@ -98,6 +102,7 @@ func (suite *KeeperTestSuite) TestRepay() {
 			},
 			errArgs{
 				expectPass:   false,
+				expectDelete: false,
 				contains:     "account can only repay up to 0bnb",
 			},
 		},
@@ -113,6 +118,7 @@ func (suite *KeeperTestSuite) TestRepay() {
 			},
 			errArgs{
 				expectPass:   false,
+				expectDelete: false,
 				contains:     "account can only repay up to 50000000ukava",
 			},
 		},
@@ -232,9 +238,15 @@ func (suite *KeeperTestSuite) TestRepay() {
 				suite.Require().Equal(expectedModuleCoins, mAcc.GetCoins())
 
 				// Check user's borrow object
-				borrow, _ := suite.keeper.GetBorrow(suite.ctx, tc.args.borrower)
+				borrow, foundBorrow := suite.keeper.GetBorrow(suite.ctx, tc.args.borrower)
 				expectedBorrowCoins := tc.args.borrowCoins.Sub(repaymentCoins)
+
+				if tc.errArgs.expectDelete {
+					suite.Require().False(foundBorrow)
+				} else {
+					suite.Require().True(foundBorrow)
 					suite.Require().Equal(expectedBorrowCoins, borrow.Amount)
+				}
 			} else {
 				suite.Require().Error(err)
 				suite.Require().True(strings.Contains(err.Error(), tc.errArgs.contains))
@@ -250,7 +262,8 @@ func (suite *KeeperTestSuite) TestRepay() {
 				suite.Require().Equal(expectedModuleCoins, mAcc.GetCoins())
 
 				// Check user's borrow object (no repay coins)
-				borrow, _ := suite.keeper.GetBorrow(suite.ctx, tc.args.borrower)
+				borrow, foundBorrow := suite.keeper.GetBorrow(suite.ctx, tc.args.borrower)
+				suite.Require().True(foundBorrow)
 				suite.Require().Equal(tc.args.borrowCoins, borrow.Amount)
 			}
 		})

x/hard/keeper/withdraw_test.go

@@ -24,11 +24,11 @@ func (suite *KeeperTestSuite) TestWithdraw() {
 		createDeposit             bool
 		expectedAccountBalance    sdk.Coins
 		expectedModAccountBalance sdk.Coins
-		depositExists             bool
 		finalDepositAmount        sdk.Coins
 	}
 	type errArgs struct {
 		expectPass   bool
+		expectDelete bool
 		contains     string
 	}
 	type withdrawTest struct {
@@ -47,11 +47,11 @@ func (suite *KeeperTestSuite) TestWithdraw() {
 				createDeposit:             true,
 				expectedAccountBalance:    sdk.NewCoins(sdk.NewCoin("bnb", sdk.NewInt(900)), sdk.NewCoin("btcb", sdk.NewInt(1000))),
 				expectedModAccountBalance: sdk.NewCoins(sdk.NewCoin("bnb", sdk.NewInt(100))),
-				depositExists:             true,
 				finalDepositAmount:        sdk.NewCoins(sdk.NewCoin("bnb", sdk.NewInt(100))),
 			},
 			errArgs{
 				expectPass:   true,
+				expectDelete: false,
 				contains:     "",
 			},
 		},
@@ -65,11 +65,11 @@ func (suite *KeeperTestSuite) TestWithdraw() {
 				createDeposit:             true,
 				expectedAccountBalance:    sdk.NewCoins(sdk.NewCoin("bnb", sdk.NewInt(1000)), sdk.NewCoin("btcb", sdk.NewInt(1000))),
 				expectedModAccountBalance: sdk.Coins(nil),
-				depositExists:             false,
 				finalDepositAmount:        sdk.Coins{},
 			},
 			errArgs{
 				expectPass:   true,
+				expectDelete: true,
 				contains:     "",
 			},
 		},
@@ -83,11 +83,11 @@ func (suite *KeeperTestSuite) TestWithdraw() {
 				createDeposit:             true,
 				expectedAccountBalance:    sdk.NewCoins(sdk.NewCoin("bnb", sdk.NewInt(1000)), sdk.NewCoin("btcb", sdk.NewInt(1000))),
 				expectedModAccountBalance: sdk.NewCoins(sdk.NewCoin("bnb", sdk.NewInt(1000))),
-				depositExists:             false,
 				finalDepositAmount:        sdk.Coins{},
 			},
 			errArgs{
 				expectPass:   true,
+				expectDelete: true,
 				contains:     "",
 			},
 		},
@@ -101,11 +101,11 @@ func (suite *KeeperTestSuite) TestWithdraw() {
 				createDeposit:             true,
 				expectedAccountBalance:    sdk.Coins{},
 				expectedModAccountBalance: sdk.Coins{},
-				depositExists:             false,
 				finalDepositAmount:        sdk.Coins{},
 			},
 			errArgs{
 				expectPass:   false,
+				expectDelete: false,
 				contains:     "no coins of this type deposited",
 			},
 		},
@@ -198,11 +198,11 @@ func (suite *KeeperTestSuite) TestWithdraw() {
 				mAcc := suite.getModuleAccount(types.ModuleAccountName)
 				suite.Require().Equal(tc.args.expectedModAccountBalance, mAcc.GetCoins())
 				testDeposit, f := suite.keeper.GetDeposit(suite.ctx, tc.args.depositor)
-				if tc.args.depositExists {
+				if tc.errArgs.expectDelete {
+					suite.Require().False(f)
+				} else {
 					suite.Require().True(f)
 					suite.Require().Equal(tc.args.finalDepositAmount, testDeposit.Amount)
-				} else {
-					suite.Require().False(f)
 				}
 			} else {
 				suite.Require().Error(err)