test(agentcompat): add integration scenarios

Co-authored-by: naiba/CloudCode <hi+cloudcode@nai.ba>

integration/agentcompat/internal/scenario/held_websocket_pump.go

@@ -0,0 +1,112 @@
+//go:build linux
+
+package scenario
+
+import (
+	"context"
+	"errors"
+	"sync"
+
+	"github.com/nezhahq/nezha/integration/agentcompat/internal/client"
+)
+
+var (
+	ErrInvalidHeldFramePump = errors.New("held WebSocket frame pump is invalid")
+	ErrHeldFrameBufferFull  = errors.New("held WebSocket frame buffer is full")
+)
+
+type heldWebSocketPump struct {
+	connection *client.WebSocketConnection
+	ctx        context.Context
+	cancel     context.CancelFunc
+	events     chan client.Frame
+	done       chan struct{}
+	stopOnce   sync.Once
+	stopDone   chan struct{}
+	stopResult error
+	terminalMu sync.RWMutex
+	terminal   error
+}
+
+func newHeldWebSocketPump(parent context.Context, connection *client.WebSocketConnection, capacity int) (*heldWebSocketPump, error) {
+	if parent == nil || connection == nil || capacity < 1 {
+		return nil, ErrInvalidHeldFramePump
+	}
+	pumpContext, cancel := context.WithCancel(parent)
+	pump := &heldWebSocketPump{connection: connection, ctx: pumpContext, cancel: cancel, events: make(chan client.Frame, capacity), done: make(chan struct{}), stopDone: make(chan struct{})}
+	go pump.readFrames()
+	return pump, nil
+}
+
+func (pump *heldWebSocketPump) Events() <-chan client.Frame { return pump.events }
+
+func (pump *heldWebSocketPump) Done() <-chan struct{} { return pump.done }
+
+func (pump *heldWebSocketPump) Err() error {
+	pump.terminalMu.RLock()
+	defer pump.terminalMu.RUnlock()
+	return pump.terminal
+}
+
+func (pump *heldWebSocketPump) readFrames() {
+	defer close(pump.events)
+	defer close(pump.done)
+	for {
+		frame, err := pump.connection.ReadFrameUntil(pump.ctx)
+		if err != nil {
+			if pump.ctx.Err() == nil {
+				pump.setTerminal(err)
+			}
+			return
+		}
+		select {
+		case pump.events <- frame:
+		case <-pump.ctx.Done():
+			return
+		default:
+			pump.setTerminal(ErrHeldFrameBufferFull)
+			pump.cancel()
+			_ = pump.connection.Close()
+			return
+		}
+	}
+}
+
+func (pump *heldWebSocketPump) setTerminal(err error) {
+	pump.terminalMu.Lock()
+	defer pump.terminalMu.Unlock()
+	if pump.terminal == nil {
+		pump.terminal = err
+	}
+}
+
+func (pump *heldWebSocketPump) Stop(ctx context.Context) error {
+	pump.stopOnce.Do(func() {
+		// The shutdown owner must outlive any individual caller's wait context.
+		go pump.stop()
+	})
+	select {
+	case <-pump.stopDone:
+		return pump.stopResult
+	case <-ctx.Done():
+		return ctx.Err()
+	}
+}
+
+func (pump *heldWebSocketPump) stop() {
+	pump.cancel()
+	closeErr := pump.connection.Close()
+	<-pump.done
+	// Publish only after the reader is joined so every waiter observes the same complete result.
+	pump.stopResult = errors.Join(pump.Err(), closeErr)
+	close(pump.stopDone)
+}
+
+func (pump *heldWebSocketPump) Wait(ctx context.Context) error {
+	select {
+	case <-pump.done:
+		return nil
+	case <-ctx.Done():
+		return ctx.Err()
+	}
+}