diff --git a/sum/sum_test.go b/sum/sum_test.go
index 81c176c..09c5c5b 100644
--- a/sum/sum_test.go
+++ b/sum/sum_test.go
@@ -28,21 +28,23 @@ func TestSumAll(t *testing.T) {
 }
 
 func TestSumAllTails(t *testing.T) {
+	checkSums := func(t *testing.T, got, exp []int) {
+		if !slices.Equal(got, exp) {
+			t.Errorf("got %d, expected %d", got, exp)
+		}
+	}
+
 	t.Run("make the sums of some slices", func(t *testing.T) {
 		got := SumAllTails([]int{1, 2}, []int{0, 9})
 		exp := []int{2, 9}
 
-		if !slices.Equal(got, exp) {
-			t.Errorf("got %d, expected %d", got, exp)
-		}
+		checkSums(t, got, exp)
 	})
 
 	t.Run("safely sum empty slices", func(t *testing.T) {
 		got := SumAllTails([]int{}, []int{3, 4, 5})
 		exp := []int{0, 9}
 
-		if !slices.Equal(got, exp) {
-			t.Errorf("got %d, expected %d", got, exp)
-		}
+		checkSums(t, got, exp)
 	})
 }