Add unit test

Signed-off-by: Lantao Liu <lantaol@google.com>

pkg/server/agents/testing/fake_agent_factory.go

@@ -0,0 +1,50 @@
+/*
+Copyright 2017 The Kubernetes 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 testing
+
+import (
+	"io"
+
+	"github.com/kubernetes-incubator/cri-containerd/pkg/server/agents"
+)
+
+// FakeAgent is a fake agent for test.
+type FakeAgent struct{}
+
+// Start always return nil not.
+// TODO(random-liu): Inject error and test error.
+func (f *FakeAgent) Start() error {
+	return nil
+}
+
+// FakeAgentFactory is a fake agent factory for test.
+type FakeAgentFactory struct{}
+
+// NewFakeAgentFactory creates fake agent factory.
+func NewFakeAgentFactory() agents.AgentFactory {
+	return &FakeAgentFactory{}
+}
+
+// NewSandboxLogger creates a fake agent as sandbox logger.
+func (*FakeAgentFactory) NewSandboxLogger(rc io.ReadCloser) agents.Agent {
+	return &FakeAgent{}
+}
+
+// NewContainerLogger creates a fake agent as container logger.
+func (*FakeAgentFactory) NewContainerLogger(string, agents.StreamType, io.ReadCloser) agents.Agent {
+	return &FakeAgent{}
+}