multi: add buffer.Write and pool.WriteBuffer, make GCQueue generic

buffer/buffer_test.go

@@ -0,0 +1,44 @@
+package buffer_test
+
+import (
+	"bytes"
+	"testing"
+
+	"github.com/lightningnetwork/lnd/buffer"
+)
+
+// TestRecycleSlice asserts that RecycleSlice always zeros a byte slice.
+func TestRecycleSlice(t *testing.T) {
+	tests := []struct {
+		name  string
+		slice []byte
+	}{
+		{
+			name: "length zero",
+		},
+		{
+			name:  "length one",
+			slice: []byte("a"),
+		},
+		{
+			name:  "length power of two length",
+			slice: bytes.Repeat([]byte("b"), 16),
+		},
+		{
+			name:  "length non power of two",
+			slice: bytes.Repeat([]byte("c"), 27),
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			buffer.RecycleSlice(test.slice)
+
+			expSlice := make([]byte, len(test.slice))
+			if !bytes.Equal(expSlice, test.slice) {
+				t.Fatalf("slice not recycled, want: %v, got: %v",
+					expSlice, test.slice)
+			}
+		})
+	}
+}