Debounce and caching

clock.go

@@ -0,0 +1,25 @@
+package main
+
+import "time"
+
+type Clock interface {
+	Now() time.Time
+}
+
+type RealClock struct{}
+
+func (RealClock) Now() time.Time {
+	return time.Now()
+}
+
+type MockClock struct {
+	currentTime time.Time
+}
+
+func (mc *MockClock) Now() time.Time {
+	return mc.currentTime
+}
+
+func (mc *MockClock) Advance(d time.Duration) {
+	mc.currentTime = mc.currentTime.Add(d)
+}