Added a few more funcs

Author: Bartlomiej Mika

constants.go

@@ -20,3 +20,19 @@ var monthAbbreviations = map[time.Month]string{
 	time.November:  "Nov",
 	time.December:  "Dec",
 }
+
+// monthNumberAbbreviations is a mapping from month numbers (1 to 12) to their three-letter abbreviations.
+var monthNumberAbbreviations = map[int]string{
+	1:  "Jan", // January
+	2:  "Feb", // February
+	3:  "Mar", // March
+	4:  "Apr", // April
+	5:  "May", // May
+	6:  "Jun", // June
+	7:  "Jul", // July
+	8:  "Aug", // August
+	9:  "Sep", // September
+	10: "Oct", // October
+	11: "Nov", // November
+	12: "Dec", // December
+}

conversion.go

@@ -80,3 +80,12 @@ func GetMonthAbbreviation(month time.Month) string {
 	}
 	return abbreviation
 }
+
+// GetMonthAbbreviationByInt returns the 3-character abbreviation for the provided month number.
+func GetMonthAbbreviationByInt(month int) string {
+	abbreviation, found := monthNumberAbbreviations[month]
+	if !found {
+		return ""
+	}
+	return abbreviation
+}

conversion_test.go

@@ -227,6 +227,7 @@ func TestGetMonthAbbreviation(t *testing.T) {
 		{time.October, "Oct"},
 		{time.November, "Nov"},
 		{time.December, "Dec"},
+		{time.January - 1, ""}, // This case should return an empty string.
 	}
 
 	for _, tc := range testCases {
@@ -238,3 +239,23 @@ func TestGetMonthAbbreviation(t *testing.T) {
 		})
 	}
 }
+
+func TestGetMonthAbbreviationByInt(t *testing.T) {
+	t.Run("ValidMonth", func(t *testing.T) {
+		month := 3
+		abbreviation := GetMonthAbbreviationByInt(month)
+		expected := "Mar"
+		if abbreviation != expected {
+			t.Errorf("Expected abbreviation for March is %s, but got %s", expected, abbreviation)
+		}
+	})
+
+	t.Run("InvalidMonth", func(t *testing.T) { // This case should return an empty string.
+		month := 13
+		abbreviation := GetMonthAbbreviationByInt(month)
+		expected := ""
+		if abbreviation != expected {
+			t.Errorf("Expected abbreviation for an invalid month is an empty string, but got %s", abbreviation)
+		}
+	})
+}