(feat) Add function to get total number of days in a BS year (#20)

dateconv/dateconv.go

@@ -3,6 +3,7 @@
 package dateconv
 
 import (
+	"fmt"
 	"time"
 )
 
@@ -72,6 +73,22 @@ func BsDaysInMonthsByYear(yy int, mm time.Month) (int, bool) {
 	return months[query], true
 }
 
+// TotalDaysInBSYear returns total number of days in a particular BS year.
+func TotalDaysInBSYear(bsYear int) (int, error) {
+	days, ok := bsDaysInMonthsByYear[bsYear]
+
+	if !ok {
+		return -1, fmt.Errorf("Year should be in between %d and %d", bsLBound, bsUBound)
+	}
+
+	sum := 0
+	for _, value := range days {
+		sum += value
+	}
+
+	return sum, nil
+}
+
 // toTime creates a new time.Time with the basic yy/mm/dd parameters.
 func toTime(yy, mm, dd int) time.Time {
 	return time.Date(yy, time.Month(mm), dd, 0, 0, 0, 0, time.UTC)

dateconv/dateconv_test.go

@@ -1,6 +1,7 @@
 package dateconv
 
 import (
+	"fmt"
 	"testing"
 	"time"
 
@@ -175,3 +176,30 @@ func TestBsDaysInMonthsByYear(t *testing.T) {
 		})
 	}
 }
+
+func TestTotalDaysInBSYear(t *testing.T) {
+	tests := []struct {
+		name     string
+		year     int
+		expected int
+	}{
+		{"returns total number of days in 2001 BS", 2001, 365},
+		{"returns total number of days in 2077 BS", 2077, 366},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			total, err := TotalDaysInBSYear(test.year)
+
+			assert.Equal(t, test.expected, total, err)
+		})
+	}
+
+	t.Run("errors if BS year is out of range", func(t *testing.T) {
+		_, err := TotalDaysInBSYear(3050)
+
+		if assert.Error(t, err) {
+			assert.Equal(t, fmt.Errorf("Year should be in between %d and %d", bsLBound, bsUBound), err)
+		}
+	})
+}