1 files changed, 28 insertions, 0 deletions
diff --git a/model/validation.go b/model/validation.go
new file mode 100644
index 0000000..d49141d
--- /dev/null
+++ b/model/validation.go
@@ -0,0 +1,28 @@
+package model
+
+import (
+	"fmt"
+	"strconv"
+)
+
+func isInt(s string) error {
+	_, err := strconv.Atoi(s)
+	if err != nil {
+		return fmt.Errorf("'%s' cannot be casted to integer", s)
+	}
+
+	return nil
+}
+
+func isPositiveOrZeroInt(s string) error {
+	i, err := strconv.Atoi(s)
+	if err != nil {
+		return fmt.Errorf("'%s' cannot be casted to integer", s)
+	}
+
+	if i < 0 {
+		return fmt.Errorf("'%s' is negative", s)
+	}
+
+	return nil
+}