From 105f7e32d0c1bea81267a5eb58bd06d293ac9693 Mon Sep 17 00:00:00 2001
From: ginuerzh <ginuerzh@gmail.com>
Date: Wed, 3 Jun 2026 23:47:54 +0800
Subject: [PATCH] test(handler/router): add observe_test.go (checkRateLimit,
 observeStats)

---
 handler/router/observe_test.go | 213 +++++++++++++++++++++++++++++++++
 1 file changed, 213 insertions(+)
 create mode 100644 handler/router/observe_test.go

diff --git a/handler/router/observe_test.go b/handler/router/observe_test.go
new file mode 100644
index 00000000..f539e59a
--- /dev/null
+++ b/handler/router/observe_test.go
@@ -0,0 +1,213 @@
+package router
+
+import (
+	"context"
+	"errors"
+	"net"
+	"sync"
+	"testing"
+	"time"
+
+	"github.com/go-gost/core/handler"
+	"github.com/go-gost/core/limiter/rate"
+	"github.com/go-gost/core/observer"
+	"github.com/go-gost/core/observer/stats"
+	stats_util "github.com/go-gost/x/internal/util/stats"
+)
+
+// ---------------------------------------------------------------------------
+// checkRateLimit tests
+// ---------------------------------------------------------------------------
+
+func TestCheckRateLimit_NilLimiter(t *testing.T) {
+	h := &routerHandler{
+		options: handler.Options{
+			RateLimiter: nil,
+		},
+	}
+	addr := &net.TCPAddr{IP: net.IPv4(10, 0, 0, 1), Port: 12345}
+	if !h.checkRateLimit(addr) {
+		t.Error("checkRateLimit returned false, want true")
+	}
+}
+
+func TestCheckRateLimit_Allowed(t *testing.T) {
+	h := &routerHandler{
+		options: handler.Options{
+			RateLimiter: &mockRateLimiterContainer{
+				limiterFn: func(key string) rate.Limiter {
+					return &mockRateLimiter{
+						allowFn: func(n int) bool { return true },
+					}
+				},
+			},
+		},
+	}
+	addr := &net.TCPAddr{IP: net.IPv4(10, 0, 0, 1), Port: 12345}
+	if !h.checkRateLimit(addr) {
+		t.Error("checkRateLimit returned false, want true")
+	}
+}
+
+func TestCheckRateLimit_Denied(t *testing.T) {
+	h := &routerHandler{
+		options: handler.Options{
+			RateLimiter: &mockRateLimiterContainer{
+				limiterFn: func(key string) rate.Limiter {
+					return &mockRateLimiter{
+						allowFn: func(n int) bool { return false },
+					}
+				},
+			},
+		},
+	}
+	addr := &net.TCPAddr{IP: net.IPv4(10, 0, 0, 1), Port: 12345}
+	if h.checkRateLimit(addr) {
+		t.Error("checkRateLimit returned true, want false")
+	}
+}
+
+func TestCheckRateLimit_LimiterByHost(t *testing.T) {
+	var gotKey string
+	h := &routerHandler{
+		options: handler.Options{
+			RateLimiter: &mockRateLimiterContainer{
+				limiterFn: func(key string) rate.Limiter {
+					gotKey = key
+					return &mockRateLimiter{
+						allowFn: func(n int) bool { return true },
+					}
+				},
+			},
+		},
+	}
+	addr := &net.TCPAddr{IP: net.IPv4(10, 0, 0, 1), Port: 12345}
+	h.checkRateLimit(addr)
+	if gotKey != "10.0.0.1" {
+		t.Errorf("limiter key = %q, want 10.0.0.1", gotKey)
+	}
+}
+
+// ---------------------------------------------------------------------------
+// observeStats tests
+// ---------------------------------------------------------------------------
+
+// newHandlerWithObserver creates a routerHandler with a fake observer.
+func newHandlerWithObserver(t *testing.T, obs *fakeObserver) *routerHandler {
+	t.Helper()
+	h := &routerHandler{
+		options: handler.Options{
+			Observer: obs,
+			Service:  "test-svc",
+		},
+		md: metadata{
+			observerPeriod:       50 * time.Millisecond,
+			observerResetTraffic: false,
+		},
+	}
+	h.stats = stats_util.NewHandlerStats("test-svc", false)
+	return h
+}
+
+func TestObserveStats_NilObserver(t *testing.T) {
+	h := &routerHandler{}
+	// Should return immediately without panic
+	h.observeStats(context.Background())
+}
+
+func TestObserveStats_NormalCycle(t *testing.T) {
+	obs := newFakeObserver(10)
+	h := newHandlerWithObserver(t, obs)
+
+	// Simulate some stat activity so Events() returns data.
+	h.stats.Stats("client-1").Add(stats.KindTotalConns, 1)
+
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	var wg sync.WaitGroup
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+		h.observeStats(ctx)
+	}()
+
+	// Wait for at least one observation cycle
+	select {
+	case <-obs.Events():
+	case <-time.After(2 * time.Second):
+		t.Fatal("timed out waiting for observer event")
+	}
+
+	cancel()
+	wg.Wait()
+}
+
+func TestObserveStats_ContextCancel(t *testing.T) {
+	obs := newFakeObserver(10)
+	h := newHandlerWithObserver(t, obs)
+
+	ctx, cancel := context.WithCancel(context.Background())
+	cancel() // cancel immediately
+
+	// Should return immediately when context is already cancelled
+	done := make(chan struct{})
+	go func() {
+		h.observeStats(ctx)
+		close(done)
+	}()
+
+	select {
+	case <-done:
+	case <-time.After(time.Second):
+		t.Fatal("observeStats did not exit after context cancel")
+	}
+}
+
+func TestObserveStats_RetryOnError(t *testing.T) {
+	var callCount int
+	var mu sync.Mutex
+	obs := &fakeObserver{
+		eventsCh: make(chan []observer.Event, 10),
+		errFunc: func() error {
+			mu.Lock()
+			callCount++
+			count := callCount
+			mu.Unlock()
+			if count <= 2 {
+				return errors.New("observer error")
+			}
+			return nil
+		},
+	}
+	h := newHandlerWithObserver(t, obs)
+
+	// Simulate stat activity so Events() returns data.
+	h.stats.Stats("client-1").Add(stats.KindTotalConns, 1)
+
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	var wg sync.WaitGroup
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+		h.observeStats(ctx)
+	}()
+
+	// Wait for successful observation (callCount > 2)
+	select {
+	case <-obs.Events():
+	case <-time.After(2 * time.Second):
+		t.Fatal("timed out waiting for successful observer event")
+	}
+
+	mu.Lock()
+	if callCount < 2 {
+		t.Errorf("callCount = %d, want at least 2 (error retries)", callCount)
+	}
+	mu.Unlock()
+
+	cancel()
+	wg.Wait()
+}
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