:sparkles: (Go) arrays and slices

Go/arrays/arrays.go

···
+package main
+
+func Sum(numbers []int) (sum int) {
+    for _, number := range numbers {
+        sum += number
+    }
+
+    return
+}
+
+func SumAll(numbersToSum ...[]int) []int {
+    var sums []int
+
+    for _, numbers := range numbersToSum {
+        sums = append(sums, Sum(numbers))
+    }
+
+    return sums
+}
+
+func SumAllTails(numbersToSum ...[]int) []int {
+    var sums []int
+
+    for _, numbers := range numbersToSum {
+        if len(numbers) == 0 {
+            sums = append(sums, 0)
+        } else {
+            tail := numbers[1:]
+            sums = append(sums, Sum(tail))
+        }
+    }
+
+    return sums
+}

Go/arrays/arrays_test.go

···
+package main
+
+import (
+    "testing"
+    "reflect"
+)
+
+func TestSum(t *testing.T) {
+    t.Run("collection of 5 numbers", func(t *testing.T) {
+        numbers := []int{1, 2, 3, 4, 5}
+
+        got := Sum(numbers)
+        want := 15
+
+        if got != want {
+            t.Errorf("got %d want %d given, %v", got, want, numbers)
+        }
+    })
+}
+
+func TestSumAll(t *testing.T) {
+    got := SumAll([]int{1, 2}, []int{0, 9})
+    want := []int{3, 9}
+
+    if !reflect.DeepEqual(got, want) {
+        t.Errorf("got %v want %v", got, want)
+    }
+}
+
+func TestSumAllTails(t *testing.T) {
+    t.Run("make the sum of some slices", func(t *testing.T) {
+        got := SumAllTails([]int{1, 2}, []int{0, 9})
+        want := []int{2, 9}
+
+        if !reflect.DeepEqual(got, want) {
+            t.Errorf("got %v want %v", got, want)
+        }
+    })
+
+    t.Run("safely sum empty slices", func(t *testing.T) {
+        got := SumAllTails([]int{}, []int{3, 4, 5})
+        want := []int{0, 9}
+
+        if !reflect.DeepEqual(got, want) {
+            t.Errorf("got %v want %v", got, want)
+        }
+    })
+}