sum: slice

sum/sum.go

@@ -1,6 +1,6 @@
 package sum
 
-func Sum(numbers [5]int) int {
+func Sum(numbers []int) int {
 	sum := 0
 
 	for _, number := range numbers {

sum/sum_test.go

@@ -3,12 +3,25 @@ package sum
 import "testing"
 
 func TestSum(t *testing.T) {
-	numbers := [5]int{1, 2, 3, 4, 5}
+	t.Run("collection of 5 numbers", func(t *testing.T) {
+		numbers := []int{1, 2, 3, 4, 5}
 
-	got := Sum(numbers)
-	exp := 15
+		got := Sum(numbers)
+		exp := 15
 
-	if got != exp {
-		t.Errorf("got %d, expected %d, given %v", got, exp, numbers)
-	}
+		if got != exp {
+			t.Errorf("got %d, expected %d, given %v", got, exp, numbers)
+		}
+	})
+
+	t.Run("collection of any size", func(t *testing.T) {
+		numbers := []int{1, 2, 3}
+
+		got := Sum(numbers)
+		exp := 6
+
+		if got != exp {
+			t.Errorf("got %d, expected %d, given %v", got, exp, numbers)
+		}
+	})
 }