Move pkg/scheduler to plugin/pkg/scheduler

As the TODO in plugin/pkg/scheduler/scheduler.go described:

move everything from pkg/scheduler into this package. Remove
references from registry.

plugin/pkg/scheduler/algorithm/scheduler_interface_test.go

@@ -0,0 +1,60 @@
+/*
+Copyright 2014 The Kubernetes Authors 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 algorithm
+
+import (
+	"testing"
+
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
+)
+
+// Some functions used by multiple scheduler tests.
+
+type schedulerTester struct {
+	t            *testing.T
+	scheduler    ScheduleAlgorithm
+	minionLister MinionLister
+}
+
+// Call if you know exactly where pod should get scheduled.
+func (st *schedulerTester) expectSchedule(pod *api.Pod, expected string) {
+	actual, err := st.scheduler.Schedule(pod, st.minionLister)
+	if err != nil {
+		st.t.Errorf("Unexpected error %v\nTried to scheduler: %#v", err, pod)
+		return
+	}
+	if actual != expected {
+		st.t.Errorf("Unexpected scheduling value: %v, expected %v", actual, expected)
+	}
+}
+
+// Call if you can't predict where pod will be scheduled.
+func (st *schedulerTester) expectSuccess(pod *api.Pod) {
+	_, err := st.scheduler.Schedule(pod, st.minionLister)
+	if err != nil {
+		st.t.Errorf("Unexpected error %v\nTried to scheduler: %#v", err, pod)
+		return
+	}
+}
+
+// Call if pod should *not* schedule.
+func (st *schedulerTester) expectFailure(pod *api.Pod) {
+	_, err := st.scheduler.Schedule(pod, st.minionLister)
+	if err == nil {
+		st.t.Error("Unexpected non-error")
+	}
+}