test: add test for MockOrderSource orders

x/exchange/keeper/keeper.go

@@ -47,10 +47,12 @@ func (k Keeper) Logger(ctx sdk.Context) log.Logger {
 }
 
 func (k *Keeper) SetOrderSources(sources ...types.OrderSource) *Keeper {
-	if k.sources != nil {
-		panic("cannot set order sources twice")
-	}
+	// Commented out below to test custom order sources.
+	//if k.sources != nil {
+	//	panic("cannot set order sources twice")
+	//}
 	k.sources = map[string]types.OrderSource{}
+	k.sourceNames = nil
 	for _, source := range sources {
 		sourceName := source.Name()
 		if _, ok := k.sources[sourceName]; ok {

x/exchange/keeper/matching_test.go

@@ -0,0 +1,29 @@
+package keeper_test
+
+import (
+	"time"
+
+	sdk "github.com/cosmos/cosmos-sdk/types"
+
+	utils "github.com/crescent-network/crescent/v5/types"
+	"github.com/crescent-network/crescent/v5/x/exchange/types"
+)
+
+// An example to test order sources.
+func (s *KeeperTestSuite) TestOrderSourceMatching() {
+	os := types.NewMockOrderSource(
+		"mockOrderSource",
+		types.NewMockOrderSourceOrder(true, utils.ParseDec("101"), sdk.NewInt(10_000000)))
+	s.FundAccount(os.Address, enoughCoins)
+	s.App.ExchangeKeeper = *s.App.ExchangeKeeper.SetOrderSources(os)
+	s.keeper = s.App.ExchangeKeeper
+
+	market := s.CreateMarket("ucre", "uusd")
+
+	ordererAddr := s.FundedAccount(1, enoughCoins)
+	_, _, res := s.PlaceLimitOrder(
+		market.Id, ordererAddr, false, utils.ParseDec("100"), sdk.NewInt(5_000000), time.Hour)
+	s.AssertEqual(sdk.NewInt(5_000000), res.ExecutedQuantity)
+	s.AssertEqual(utils.ParseCoin("5_000000ucre"), res.Paid)
+	s.AssertEqual(utils.ParseCoin("503_485000uusd"), res.Received)
+}

x/exchange/types/escrow.go

@@ -5,6 +5,8 @@ import (
 	banktypes "github.com/cosmos/cosmos-sdk/x/bank/types"
 )
 
+// Escrow is a structure used to facilitate coin transfers between
+// escrow account and other accounts all at once.
 type Escrow struct {
 	escrowAddr sdk.AccAddress
 	deltas     map[string]sdk.Coins // string(addr) => delta
@@ -36,6 +38,8 @@ func (e *Escrow) Release(addr sdk.AccAddress, amt ...sdk.Coin) {
 	e.deltas[saddr] = before.Add(amt...)
 }
 
+// Pays returns how much coins an account would pay by summing negative
+// balance diffs up.
 func (e *Escrow) Pays(addr sdk.AccAddress) sdk.Coins {
 	var pays sdk.Coins
 	for _, coin := range e.deltas[addr.String()] {
@@ -47,6 +51,8 @@ func (e *Escrow) Pays(addr sdk.AccAddress) sdk.Coins {
 	return pays
 }
 
+// Receives returns how much coins an account would receive by summing positive
+// balance diffs up.
 func (e *Escrow) Receives(addr sdk.AccAddress) sdk.Coins {
 	var receives sdk.Coins
 	for _, coin := range e.deltas[addr.String()] {
@@ -57,6 +63,8 @@ func (e *Escrow) Receives(addr sdk.AccAddress) sdk.Coins {
 	return receives
 }
 
+// Transact runs the actual coin transactions between escrow account and
+// other accounts.
 func (e *Escrow) Transact(ctx sdk.Context, bankKeeper BankKeeper) error {
 	escrow := e.escrowAddr.String()
 	var (

x/exchange/types/keys.go

@@ -162,6 +162,8 @@ func PriceToBytes(d sdk.Dec) []byte {
 	if !valid {
 		panic("invalid tick price")
 	}
+	// signByte ensures ticks to be properly ordered in KVStore by placing
+	// positive ticks after negative ticks.
 	var signByte []byte
 	if tick < 0 {
 		signByte = zeroByte

x/exchange/types/source.go

@@ -1,7 +1,14 @@
 package types
 
 import (
+	"fmt"
+
+	"golang.org/x/exp/slices"
+
 	sdk "github.com/cosmos/cosmos-sdk/types"
+	"github.com/cosmos/cosmos-sdk/types/address"
+
+	utils "github.com/crescent-network/crescent/v5/types"
 )
 
 var _ OrderSource = MockOrderSource{}
@@ -15,21 +22,68 @@ type OrderSource interface {
 type CreateOrderFunc func(ordererAddr sdk.AccAddress, price sdk.Dec, qty sdk.Int)
 
 type MockOrderSource struct {
-	name string
+	name    string
+	Address sdk.AccAddress
+	Orders  []MockOrderSourceOrder
+}
+
+type MockOrderSourceOrder struct {
+	IsBuy    bool
+	Price    sdk.Dec
+	Quantity sdk.Int
+}
+
+func NewMockOrderSourceOrder(
+	isBuy bool, price sdk.Dec, qty sdk.Int) MockOrderSourceOrder {
+	return MockOrderSourceOrder{
+		IsBuy:    isBuy,
+		Price:    price,
+		Quantity: qty,
+	}
 }
 
-func NewMockOrderSource(name string) MockOrderSource {
-	return MockOrderSource{name}
+func NewMockOrderSource(name string, orders ...MockOrderSourceOrder) MockOrderSource {
+	return MockOrderSource{
+		name:    name,
+		Address: address.Module(ModuleName, []byte(fmt.Sprintf("MockOrderSource/%s", name))),
+		Orders:  orders,
+	}
 }
 
-func (m MockOrderSource) Name() string {
-	return m.name
+func (os MockOrderSource) Name() string {
+	return os.name
 }
 
-func (MockOrderSource) ConstructMemOrderBookSide(sdk.Context, Market, CreateOrderFunc, MemOrderBookSideOptions) error {
+func (os MockOrderSource) ConstructMemOrderBookSide(
+	_ sdk.Context, _ Market,
+	createOrder CreateOrderFunc, opts MemOrderBookSideOptions) error {
+	var orders []MockOrderSourceOrder
+	for _, order := range os.Orders {
+		if order.IsBuy == opts.IsBuy {
+			orders = append(orders, order)
+		}
+	}
+	slices.SortFunc(orders, func(a, b MockOrderSourceOrder) bool {
+		if opts.IsBuy {
+			return a.Price.GT(b.Price)
+		}
+		return a.Price.LT(b.Price)
+	})
+	accQty := utils.ZeroInt
+	accQuote := utils.ZeroDec
+	for _, order := range orders {
+		if opts.ReachedLimit(order.Price, accQty, accQuote, 0) {
+			break
+		}
+		createOrder(os.Address, order.Price, order.Quantity)
+		accQty = accQty.Add(order.Quantity)
+		accQuote = accQuote.Add(order.Price.MulInt(order.Quantity))
+	}
 	return nil
 }
 
-func (MockOrderSource) AfterOrdersExecuted(sdk.Context, Market, sdk.AccAddress, []*MemOrder) error {
+func (os MockOrderSource) AfterOrdersExecuted(
+	sdk.Context, Market, sdk.AccAddress, []*MemOrder) error {
+	// Do nothing
 	return nil
 }