Add cron.Machine state machine.

scheduler/appengine/engine/cron/machine_test.go

Index: scheduler/appengine/engine/cron/machine_test.go
diff --git a/scheduler/appengine/engine/cron/machine_test.go b/scheduler/appengine/engine/cron/machine_test.go
new file mode 100644
index 0000000000000000000000000000000000000000..04a02f6dcf4a5055e2ab4a392ba72a6669c28f4d
--- /dev/null
+++ b/scheduler/appengine/engine/cron/machine_test.go
@@ -0,0 +1,23 @@
+// Copyright 2017 The LUCI Authors.
+//
+// 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 cron
+
+import (
+	"testing"
+)
+
+func TestMachine(t *testing.T) {
+	// TODO
+}