tests for amount out

service/get_amount_out_test.go

@@ -0,0 +1,93 @@
+package service
+
+import (
+	"testing"
+
+	"github.com/orbs-network/order-book/models"
+	"github.com/shopspring/decimal"
+	"github.com/stretchr/testify/assert"
+)
+
+// /////////////////////////////////////////////////////////////////
+// static iterator impl
+type iter struct {
+	orders []models.Order
+	index  int
+}
+
+func (i *iter) HasNext() bool {
+	return i.index < (len(i.orders) - 1)
+}
+func (i *iter) Next() *models.Order {
+	// increment index
+	i.index = i.index + 1
+
+	if i.index >= len(i.orders) {
+		return nil
+	}
+
+	// get order
+	return &i.orders[i.index]
+}
+
+func newOrder(price, size int64) models.Order {
+	return models.Order{
+		Price: decimal.NewFromInt(price),
+		Size:  decimal.NewFromInt(size),
+	}
+
+}
+
+// /////////////////////////////////////////////////////////////////
+func TestService_getAmountOutInAToken(t *testing.T) {
+	// create order book
+	itAsk := iter{
+		orders: []models.Order{
+			newOrder(1000, 1),
+			newOrder(1001, 2),
+			newOrder(1002, 3),
+		},
+		index: -1,
+	}
+	itBid := iter{
+		orders: []models.Order{
+			newOrder(900, 1),
+			newOrder(800, 2),
+			newOrder(700, 3),
+		},
+		index: -1,
+	}
+	t.Run("getAmountOutInAToken- happy path", func(t *testing.T) {
+		res, err := getAmountOutInAToken(&itAsk, decimal.NewFromFloat((1000*1)+(1001*2)+(1002*3)))
+		assert.Equal(t, err, nil)
+		assert.Equal(t, res.AmountOut.String(), decimal.NewFromFloat(1+2+3).String())
+	})
+	t.Run("getAmountOutInAToken- Partial fill", func(t *testing.T) {
+		res, err := getAmountOutInAToken(&itAsk, decimal.NewFromFloat(501))
+		assert.Equal(t, err, nil)
+		assert.Equal(t, res.AmountOut.String(), decimal.NewFromFloat(0.501).String())
+	})
+
+	t.Run("getAmountOutInAToken- liquidity insufiicinet", func(t *testing.T) {
+		_, err := getAmountOutInAToken(&itAsk, decimal.NewFromFloat((1000*1)+(1001*2)+(1002*3)+1))
+		assert.Equal(t, err, models.ErrInsufficientLiquity)
+	})
+
+	t.Run("getAmountOutInBToken- happy path", func(t *testing.T) {
+		res, err := getAmountOutInBToken(&itBid, decimal.NewFromFloat(1+2+3))
+		assert.Equal(t, err, nil)
+		assert.Equal(t, res.AmountOut.String(), decimal.NewFromFloat((900*1)+(800*2)+(700*3)).String())
+	})
+
+	t.Run("getAmountOutInBToken- Partial fill", func(t *testing.T) {
+		fract := 0.501
+		res, err := getAmountOutInBToken(&itBid, decimal.NewFromFloat(fract))
+		assert.Equal(t, err, nil)
+		assert.Equal(t, res.AmountOut.String(), decimal.NewFromFloat(900*fract).String())
+	})
+
+	t.Run("getAmountOutInBToken- liquidity insufiicinet", func(t *testing.T) {
+		_, err := getAmountOutInBToken(&itBid, decimal.NewFromFloat(1+2+3+1))
+		assert.Equal(t, err, models.ErrInsufficientLiquity)
+	})
+}