fix: handle unknown or invalid periods for date ranges

Author: howeyc

date.go

@@ -81,6 +81,8 @@ func getDateBoundaries(per Period, start, end time.Time) []time.Time {
 	case PeriodYear:
 		incYear = 1
 		periodStart = time.Date(start.Year(), time.January, 1, 0, 0, 0, 0, time.UTC)
+	default:
+		return []time.Time{start, end}
 	}
 
 	boundaries := []time.Time{periodStart}

date_test.go

@@ -0,0 +1,59 @@
+package ledger
+
+import (
+	"testing"
+	"time"
+)
+
+type boundCase struct {
+	period     Period
+	start, end time.Time
+	bounds     []time.Time
+}
+
+var boundCases = []boundCase{
+	{
+		PeriodYear,
+		time.Date(2019, time.March, 23, 0, 0, 0, 0, time.UTC),
+		time.Date(2021, time.March, 23, 0, 0, 0, 0, time.UTC),
+		[]time.Time{
+			time.Date(2019, time.January, 01, 0, 0, 0, 0, time.UTC),
+			time.Date(2020, time.January, 01, 0, 0, 0, 0, time.UTC),
+			time.Date(2021, time.January, 01, 0, 0, 0, 0, time.UTC),
+			time.Date(2022, time.January, 01, 0, 0, 0, 0, time.UTC),
+		},
+	},
+	{
+		PeriodMonth,
+		time.Date(2019, time.March, 23, 0, 0, 0, 0, time.UTC),
+		time.Date(2019, time.April, 23, 0, 0, 0, 0, time.UTC),
+		[]time.Time{
+			time.Date(2019, time.March, 01, 0, 0, 0, 0, time.UTC),
+			time.Date(2019, time.April, 01, 0, 0, 0, 0, time.UTC),
+			time.Date(2019, time.May, 01, 0, 0, 0, 0, time.UTC),
+		},
+	},
+	{
+		Period("Unknown"),
+		time.Date(2019, time.March, 23, 0, 0, 0, 0, time.UTC),
+		time.Date(2019, time.April, 23, 0, 0, 0, 0, time.UTC),
+		[]time.Time{
+			time.Date(2019, time.March, 23, 0, 0, 0, 0, time.UTC),
+			time.Date(2019, time.April, 23, 0, 0, 0, 0, time.UTC),
+		},
+	},
+}
+
+func TestDateBoundaries(t *testing.T) {
+	for _, tc := range boundCases {
+		bounds := getDateBoundaries(tc.period, tc.start, tc.end)
+		if len(bounds) != len(tc.bounds) {
+			t.Fatalf("Error(%s): expected `%d` bounds, got `%d` bounds", tc.period, len(tc.bounds), len(bounds))
+		}
+		for i, b := range bounds {
+			if !b.Equal(tc.bounds[i]) {
+				t.Errorf("Error(%s): expected [%d] = `%s` , got `%s`", tc.period, i, tc.bounds[i].Format(time.RFC3339), b.Format(time.RFC3339))
+			}
+		}
+	}
+}