trade: extract sql generator function and test it

pkg/service/trade.go

@@ -36,10 +36,6 @@ func NewTradeService(db *sqlx.DB) *TradeService {
 }
 
 func (s *TradeService) QueryTradingVolume(startTime time.Time, options TradingVolumeQueryOptions) ([]TradingVolume, error) {
-	var sel []string
-	var groupBys []string
-	var orderBys []string
-	where := []string{"traded_at > :start_time"}
 	args := map[string]interface{}{
 		// "symbol":      symbol,
 		// "exchange":    ex,
@@ -48,6 +44,39 @@ func (s *TradeService) QueryTradingVolume(startTime time.Time, options TradingVo
 		"start_time": startTime,
 	}
 
+	sql := queryTradingVolumeSQL(options)
+
+	rows, err := s.DB.NamedQuery(sql, args)
+	if err != nil {
+		return nil, errors.Wrap(err, "query last trade error")
+	}
+
+	if rows.Err() != nil {
+		return nil, rows.Err()
+	}
+
+	defer rows.Close()
+
+	var records []TradingVolume
+	for rows.Next() {
+		var record TradingVolume
+		err = rows.StructScan(&record)
+		if err != nil {
+			return records, err
+		}
+
+		record.Time = time.Date(record.Year, time.Month(record.Month), record.Day, 0, 0, 0, 0, time.UTC)
+		records = append(records, record)
+	}
+
+	return records, rows.Err()
+}
+
+func queryTradingVolumeSQL(options TradingVolumeQueryOptions) string {
+	var sel []string
+	var groupBys []string
+	var orderBys []string
+	where := []string{"traded_at > :start_time"}
 	switch options.GroupByPeriod {
 
 	case "month":
@@ -87,31 +116,7 @@ func (s *TradeService) QueryTradingVolume(startTime time.Time, options TradingVo
 		` ORDER BY ` + strings.Join(orderBys, ", ")
 
 	log.Info(sql)
-
+	return sql
-	rows, err := s.DB.NamedQuery(sql, args)
-	if err != nil {
-		return nil, errors.Wrap(err, "query last trade error")
-	}
-
-	if rows.Err() != nil {
-		return nil, rows.Err()
-	}
-
-	defer rows.Close()
-
-	var records []TradingVolume
-	for rows.Next() {
-		var record TradingVolume
-		err = rows.StructScan(&record)
-		if err != nil {
-			return records, err
-		}
-
-		record.Time = time.Date(record.Year, time.Month(record.Month), record.Day, 0, 0, 0, 0, time.UTC)
-		records = append(records, record)
-	}
-
-	return records, rows.Err()
 }
 
 // QueryLast queries the last trade from the database
@@ -158,10 +163,12 @@ func (s *TradeService) QueryForTradingFeeCurrency(ex types.ExchangeName, symbol
 	return s.scanRows(rows)
 }
 
+// Only return 500 items.
 type QueryTradesOptions struct {
 	Exchange types.ExchangeName
 	Symbol   string
 	LastGID  int64
+	// ASC or DESC
 	Ordering string
 }
 

pkg/service/trade_test.go

@@ -0,0 +1,57 @@
+package service
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func Test_queryTradingVolumeSQL(t *testing.T) {
+	t.Run("group by different period", func(t *testing.T) {
+		o := TradingVolumeQueryOptions{
+			GroupByPeriod: "month",
+		}
+		assert.Equal(t, "SELECT YEAR(traded_at) AS year, MONTH(traded_at) AS month, SUM(quantity * price) AS quote_volume FROM trades WHERE traded_at > :start_time GROUP BY MONTH(traded_at), YEAR(traded_at) ORDER BY year ASC, month ASC", queryTradingVolumeSQL(o))
+
+		o.GroupByPeriod = "year"
+		assert.Equal(t, "SELECT YEAR(traded_at) AS year, SUM(quantity * price) AS quote_volume FROM trades WHERE traded_at > :start_time GROUP BY YEAR(traded_at) ORDER BY year ASC", queryTradingVolumeSQL(o))
+
+		expectedDefaultSQL := "SELECT YEAR(traded_at) AS year, MONTH(traded_at) AS month, DAY(traded_at) AS day, SUM(quantity * price) AS quote_volume FROM trades WHERE traded_at > :start_time GROUP BY DAY(traded_at), MONTH(traded_at), YEAR(traded_at) ORDER BY year ASC, month ASC, day ASC"
+		for _, s := range []string{"", "day"} {
+			o.GroupByPeriod = s
+			assert.Equal(t, expectedDefaultSQL, queryTradingVolumeSQL(o))
+		}
+	})
+
+}
+
+func Test_queryTradesSQL(t *testing.T) {
+	t.Run("generate order by clause by Ordering option", func(t *testing.T) {
+		assert.Equal(t, "SELECT * FROM trades ORDER BY gid ASC LIMIT 500", queryTradesSQL(QueryTradesOptions{}))
+		assert.Equal(t, "SELECT * FROM trades ORDER BY gid ASC LIMIT 500", queryTradesSQL(QueryTradesOptions{Ordering: "ASC"}))
+		assert.Equal(t, "SELECT * FROM trades ORDER BY gid DESC LIMIT 500", queryTradesSQL(QueryTradesOptions{Ordering: "DESC"}))
+	})
+
+	t.Run("filter by exchange name", func(t *testing.T) {
+		assert.Equal(t, "SELECT * FROM trades WHERE exchange = :exchange ORDER BY gid ASC LIMIT 500", queryTradesSQL(QueryTradesOptions{Exchange: "max"}))
+	})
+
+	t.Run("filter by symbol", func(t *testing.T) {
+		assert.Equal(t, "SELECT * FROM trades WHERE symbol = :symbol ORDER BY gid ASC LIMIT 500", queryTradesSQL(QueryTradesOptions{Symbol: "eth"}))
+	})
+
+	t.Run("GID ordering", func(t *testing.T) {
+		assert.Equal(t, "SELECT * FROM trades WHERE gid > :gid ORDER BY gid ASC LIMIT 500", queryTradesSQL(QueryTradesOptions{LastGID: 1}))
+		assert.Equal(t, "SELECT * FROM trades WHERE gid > :gid ORDER BY gid ASC LIMIT 500", queryTradesSQL(QueryTradesOptions{LastGID: 1, Ordering: "ASC"}))
+		assert.Equal(t, "SELECT * FROM trades WHERE gid < :gid ORDER BY gid DESC LIMIT 500", queryTradesSQL(QueryTradesOptions{LastGID: 1, Ordering: "DESC"}))
+	})
+
+	t.Run("convert all options", func(t *testing.T) {
+		assert.Equal(t, "SELECT * FROM trades WHERE exchange = :exchange AND symbol = :symbol AND gid < :gid ORDER BY gid DESC LIMIT 500", queryTradesSQL(QueryTradesOptions{
+			Exchange: "max",
+			Symbol:   "btc",
+			LastGID:  123,
+			Ordering: "DESC",
+		}))
+	})
+}