time: days_in_month()

vlib/time/time_test.v

@@ -14,4 +14,26 @@ fn test_is_leap_year() {
 
     assert time.is_leap_year(1996) == true
     assert time.is_leap_year(1997) == false
-}
+}
+
+fn check(month, year, expectedDays int) bool {
+	return time.days_in_month(month, year) or {
+		return false
+	}
+}
+
+fn test_days_in_month() {
+	assert check(1, 2001, 31) // January
+	assert check(2, 2001, 28) // February
+	assert check(2, 2000, 29) // February (leap)
+	assert check(3, 2001, 31) // March
+	assert check(4, 2001, 30) // April
+	assert check(5, 2001, 31) // May
+	assert check(6, 2001, 30) // June
+	assert check(7, 2001, 31) // July
+	assert check(8, 2001, 31) // August
+	assert check(9, 2001, 30) // September
+	assert check(10, 2001, 31) // October
+	assert check(11, 2001, 30) // November
+	assert check(12, 2001, 31) // December
+}