first commit

validasi/validasi.go

@@ -0,0 +1,19 @@
+package validasi
+
+import "fmt"
+
+// IsUsiaProduktif returns true if age is between 18 and 60 inclusive.
+func IsUsiaProduktif(age int) bool {
+    return age >= 18 && age <= 60
+}
+
+// ValidateUsia returns nil when usia produktif, otherwise an error explaining why.
+func ValidateUsia(age int) error {
+    if age < 0 {
+        return fmt.Errorf("umur tidak boleh negatif")
+    }
+    if IsUsiaProduktif(age) {
+        return nil
+    }
+    return fmt.Errorf("umur %d bukan usia produktif (18-60)", age)
+}

validasi/validasi_test.go

@@ -0,0 +1,38 @@
+package validasi
+
+import "testing"
+
+func TestIsUsiaProduktif(t *testing.T) {
+    cases := []struct{
+        age int
+        want bool
+    }{
+        {17, false},
+        {18, true},
+        {30, true},
+        {60, true},
+        {61, false},
+    }
+
+    for _, c := range cases {
+        got := IsUsiaProduktif(c.age)
+        if got != c.want {
+            t.Fatalf("IsUsiaProduktif(%d) = %v; want %v", c.age, got, c.want)
+        }
+    }
+}
+
+func TestValidateUsia(t *testing.T) {
+    if err := ValidateUsia(-1); err == nil {
+        t.Fatalf("expected error for negative age")
+    }
+    if err := ValidateUsia(18); err != nil {
+        t.Fatalf("unexpected error for age 18: %v", err)
+    }
+    if err := ValidateUsia(60); err != nil {
+        t.Fatalf("unexpected error for age 60: %v", err)
+    }
+    if err := ValidateUsia(61); err == nil {
+        t.Fatalf("expected error for age 61")
+    }
+}