Move clock to util

pkg/util/clock.go

@@ -0,0 +1,45 @@
+/*
+Copyright 2014 Google Inc. All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package util
+
+import (
+	"time"
+)
+
+// Clock allows for injecting fake or real clocks into code that
+// needs to do arbitrary things based on time.
+type Clock interface {
+	Now() time.Time
+}
+
+// RealClock really calls time.Now()
+type RealClock struct{}
+
+// Now returns the current time.
+func (r RealClock) Now() time.Time {
+	return time.Now()
+}
+
+// FakeClock implements Clock, but returns an arbitary time.
+type FakeClock struct {
+	Time time.Time
+}
+
+// Now returns f's time.
+func (f *FakeClock) Now() time.Time {
+	return f.Time
+}