diff --git a/pkg/calc.go b/pkg/calc.go
index d33941d..3c1cb20 100644
--- a/pkg/calc.go
+++ b/pkg/calc.go
@@ -17,3 +17,7 @@ func Clamp(x, lo, hi int) int {
 	}
 	return x
 }
+
+func IncThird(x int) int {
+	return x + 1
+}
diff --git a/pkg/calc_test.go b/pkg/calc_test.go
index 607ef2d..95b46c0 100644
--- a/pkg/calc_test.go
+++ b/pkg/calc_test.go
@@ -7,6 +7,7 @@ func TestInc(t *testing.T) {
 		t.Fatal("inc")
 	}
 	_ = IncAgain(1)
+	_ = IncThird(1)
 }
 
 func TestClamp(t *testing.T) {