test(agentcompat): add integration scenarios

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

integration/agentcompat/internal/scenario/held_nat_request.go

@@ -0,0 +1,56 @@
+//go:build linux
+
+package scenario
+
+import (
+	"bufio"
+	"context"
+	"fmt"
+	"io"
+	"net"
+	"net/http"
+	"sync"
+
+	"github.com/nezhahq/nezha/integration/agentcompat/internal/client"
+	"github.com/nezhahq/nezha/pkg/agentcompatcontract"
+)
+
+type heldNATRequest struct {
+	connection net.Conn
+	result     chan error
+	closeOnce  sync.Once
+	closeErr   error
+}
+
+func startHeldNATRequest(ctx context.Context, endpoint, domain, identity string, capability client.IOStreamCapability) (*heldNATRequest, error) {
+	connection, err := (&net.Dialer{}).DialContext(ctx, "tcp", endpoint)
+	if err != nil {
+		return nil, err
+	}
+	request := &heldNATRequest{connection: connection, result: make(chan error, 1)}
+	method := "PATCH"
+	path := "/held/" + identity
+	body := "held-body-" + identity
+	go func() {
+		wire := fmt.Sprintf("%s %s HTTP/1.1\r\nHost: %s\r\nX-AgentCompat-Echo: %s\r\n%s: %s\r\nContent-Length: %d\r\nConnection: close\r\n\r\n%s", method, path, domain, identity, agentcompatcontract.IOStreamCapabilityHeader, capability.Value(), len(body), body)
+		_, requestErr := io.WriteString(connection, wire)
+		if requestErr == nil {
+			response, readErr := http.ReadResponse(bufio.NewReader(connection), nil)
+			if readErr == nil {
+				_, readErr = io.Copy(io.Discard, response.Body)
+				closeErr := response.Body.Close()
+				if readErr == nil {
+					readErr = closeErr
+				}
+			}
+			requestErr = readErr
+		}
+		request.result <- requestErr
+	}()
+	return request, nil
+}
+
+func (request *heldNATRequest) close() error {
+	request.closeOnce.Do(func() { request.closeErr = request.connection.Close() })
+	return request.closeErr
+}