fix(mcp): harden dashboard dispatch lifecycle

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

cmd/dashboard/controller/mcp_ratelimit_clock_test.go

@@ -0,0 +1,45 @@
+package controller
+
+import (
+	"sync"
+	"testing"
+	"time"
+)
+
+type linearizationClock struct {
+	mu     sync.Mutex
+	times  []time.Time
+	latest time.Time
+}
+
+func newLinearizationClock(oldTime, newTime time.Time) *linearizationClock {
+	return &linearizationClock{
+		times:  []time.Time{oldTime, oldTime, newTime},
+		latest: newTime,
+	}
+}
+
+func (clock *linearizationClock) Now() time.Time {
+	clock.mu.Lock()
+	now := clock.latest
+	if len(clock.times) > 0 {
+		now = clock.times[0]
+		clock.times = clock.times[1:]
+	}
+	clock.mu.Unlock()
+	return now
+}
+
+func TestLinearizationClockReturnsLatestTimeAfterSequenceIsConsumed(t *testing.T) {
+	oldTime := time.Unix(1_700_000_000, 0)
+	newTime := oldTime.Add(time.Second)
+	clock := newLinearizationClock(oldTime, newTime)
+
+	for range 3 {
+		clock.Now()
+	}
+
+	if got := clock.Now(); !got.Equal(newTime) {
+		t.Fatalf("clock returned %s after sequence was consumed, want %s", got, newTime)
+	}
+}