Add more test cases and add UniqueValues check

internal/validator/validator.go

@@ -67,3 +67,16 @@ func GreaterThanOrEquals(value int, n int) bool {
 func After(value time.Time, n time.Time) bool {
 	return value.After(n)
 }
+
+func UniqueValues[T comparable](values []T) bool {
+	seen := make(map[T]bool)
+
+	for _, value := range values {
+		if seen[value] {
+			return false
+		}
+		seen[value] = true
+	}
+
+	return true
+}