feat(app/edge-stacks): summarize the edge stack statuses in the backend (#818)

api/slicesx/flatten_test.go

@@ -0,0 +1,19 @@
+package slicesx_test
+
+import (
+	"testing"
+
+	"github.com/portainer/portainer/api/slicesx"
+	"github.com/stretchr/testify/assert"
+)
+
+func Test_Flatten(t *testing.T) {
+	t.Run("Flatten an array of arrays", func(t *testing.T) {
+		is := assert.New(t)
+
+		source := [][]int{{1, 2, 3}, {4, 5, 6}, {7, 8, 9}}
+		expected := []int{1, 2, 3, 4, 5, 6, 7, 8, 9}
+		is.ElementsMatch(slicesx.Flatten(source), expected)
+
+	})
+}