Add daemon client protocol frames

internal/protocol/loopback_test.go

@@ -0,0 +1,51 @@
+package protocol
+
+import "testing"
+
+func TestLoopbackUsesFramePayload(t *testing.T) {
+	client, daemon := NewLoopbackPair()
+	defer client.Close()
+	defer daemon.Close()
+
+	sent, err := NewFrame(FrameInput, Input{PaneID: "p_123456", Bytes: []byte("hello")})
+	if err != nil {
+		t.Fatalf("NewFrame: %v", err)
+	}
+	if err := client.Send(sent); err != nil {
+		t.Fatalf("Send: %v", err)
+	}
+	got, err := daemon.Recv()
+	if err != nil {
+		t.Fatalf("Recv: %v", err)
+	}
+	if got.Type != FrameInput {
+		t.Fatalf("type = %q, want %q", got.Type, FrameInput)
+	}
+	payload, err := Decode[Input](got)
+	if err != nil {
+		t.Fatalf("Decode: %v", err)
+	}
+	if payload.PaneID != "p_123456" || string(payload.Bytes) != "hello" {
+		t.Fatalf("payload = %#v", payload)
+	}
+}
+
+func TestLoopbackCopiesPayloadOnSend(t *testing.T) {
+	client, daemon := NewLoopbackPair()
+	defer client.Close()
+	defer daemon.Close()
+
+	f := Frame{Type: FramePaneChunk, Payload: []byte(`{"pane_id":"p","bytes":"aGVsbG8="}`)}
+	if err := client.Send(f); err != nil {
+		t.Fatalf("Send: %v", err)
+	}
+	f.Payload[0] = 'x'
+
+	got, err := daemon.Recv()
+	if err != nil {
+		t.Fatalf("Recv: %v", err)
+	}
+	if got.Payload[0] != '{' {
+		t.Fatalf("payload was retained instead of copied: %q", string(got.Payload))
+	}
+}