/*
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 predicates

import (
	"reflect"
	"testing"

	v1 "k8s.io/api/core/v1"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/labels"
	nodeinfosnapshot "k8s.io/kubernetes/pkg/scheduler/nodeinfo/snapshot"
	st "k8s.io/kubernetes/pkg/scheduler/testing"
)

func TestGetTPMapMatchingSpreadConstraints(t *testing.T) {
	fooSelector := st.MakeLabelSelector().Exists("foo").Obj()
	barSelector := st.MakeLabelSelector().Exists("bar").Obj()
	tests := []struct {
		name         string
		pod          *v1.Pod
		nodes        []*v1.Node
		existingPods []*v1.Pod
		want         *PodTopologySpreadMetadata
	}{
		{
			name: "clean cluster with one spreadConstraint",
			pod: st.MakePod().Name("p").Label("foo", "").SpreadConstraint(
				5, "zone", hardSpread, st.MakeLabelSelector().Label("foo", "bar").Obj(),
			).Obj(),
			nodes: []*v1.Node{
				st.MakeNode().Name("node-a").Label("zone", "zone1").Label("node", "node-a").Obj(),
				st.MakeNode().Name("node-b").Label("zone", "zone1").Label("node", "node-b").Obj(),
				st.MakeNode().Name("node-x").Label("zone", "zone2").Label("node", "node-x").Obj(),
				st.MakeNode().Name("node-y").Label("zone", "zone2").Label("node", "node-y").Obj(),
			},
			want: &PodTopologySpreadMetadata{
				constraints: []topologySpreadConstraint{
					{
						maxSkew:     5,
						topologyKey: "zone",
						selector:    mustConvertLabelSelectorAsSelector(t, st.MakeLabelSelector().Label("foo", "bar").Obj()),
					},
				},
				tpKeyToCriticalPaths: map[string]*criticalPaths{
					"zone": {{"zone1", 0}, {"zone2", 0}},
				},
				tpPairToMatchNum: map[topologyPair]int32{
					{key: "zone", value: "zone1"}: 0,
					{key: "zone", value: "zone2"}: 0,
				},
			},
		},
		{
			name: "normal case with one spreadConstraint",
			pod: st.MakePod().Name("p").Label("foo", "").SpreadConstraint(
				1, "zone", hardSpread, fooSelector,
			).Obj(),
			nodes: []*v1.Node{
				st.MakeNode().Name("node-a").Label("zone", "zone1").Label("node", "node-a").Obj(),
				st.MakeNode().Name("node-b").Label("zone", "zone1").Label("node", "node-b").Obj(),
				st.MakeNode().Name("node-x").Label("zone", "zone2").Label("node", "node-x").Obj(),
				st.MakeNode().Name("node-y").Label("zone", "zone2").Label("node", "node-y").Obj(),
			},
			existingPods: []*v1.Pod{
				st.MakePod().Name("p-a1").Node("node-a").Label("foo", "").Obj(),
				st.MakePod().Name("p-a2").Node("node-a").Label("foo", "").Obj(),
				st.MakePod().Name("p-b1").Node("node-b").Label("foo", "").Obj(),
				st.MakePod().Name("p-y1").Node("node-y").Label("foo", "").Obj(),
				st.MakePod().Name("p-y2").Node("node-y").Label("foo", "").Obj(),
			},
			want: &PodTopologySpreadMetadata{
				constraints: []topologySpreadConstraint{
					{
						maxSkew:     1,
						topologyKey: "zone",
						selector:    mustConvertLabelSelectorAsSelector(t, fooSelector),
					},
				},
				tpKeyToCriticalPaths: map[string]*criticalPaths{
					"zone": {{"zone2", 2}, {"zone1", 3}},
				},
				tpPairToMatchNum: map[topologyPair]int32{
					{key: "zone", value: "zone1"}: 3,
					{key: "zone", value: "zone2"}: 2,
				},
			},
		},
		{
			name: "normal case with one spreadConstraint, on a 3-zone cluster",
			pod: st.MakePod().Name("p").Label("foo", "").SpreadConstraint(
				1, "zone", hardSpread, st.MakeLabelSelector().Exists("foo").Obj(),
			).Obj(),
			nodes: []*v1.Node{
				st.MakeNode().Name("node-a").Label("zone", "zone1").Label("node", "node-a").Obj(),
				st.MakeNode().Name("node-b").Label("zone", "zone1").Label("node", "node-b").Obj(),
				st.MakeNode().Name("node-x").Label("zone", "zone2").Label("node", "node-x").Obj(),
				st.MakeNode().Name("node-y").Label("zone", "zone2").Label("node", "node-y").Obj(),
				st.MakeNode().Name("node-o").Label("zone", "zone3").Label("node", "node-o").Obj(),
				st.MakeNode().Name("node-p").Label("zone", "zone3").Label("node", "node-p").Obj(),
			},
			existingPods: []*v1.Pod{
				st.MakePod().Name("p-a1").Node("node-a").Label("foo", "").Obj(),
				st.MakePod().Name("p-a2").Node("node-a").Label("foo", "").Obj(),
				st.MakePod().Name("p-b1").Node("node-b").Label("foo", "").Obj(),
				st.MakePod().Name("p-y1").Node("node-y").Label("foo", "").Obj(),
				st.MakePod().Name("p-y2").Node("node-y").Label("foo", "").Obj(),
			},
			want: &PodTopologySpreadMetadata{
				constraints: []topologySpreadConstraint{
					{
						maxSkew:     1,
						topologyKey: "zone",
						selector:    mustConvertLabelSelectorAsSelector(t, fooSelector),
					},
				},
				tpKeyToCriticalPaths: map[string]*criticalPaths{
					"zone": {{"zone3", 0}, {"zone2", 2}},
				},
				tpPairToMatchNum: map[topologyPair]int32{
					{key: "zone", value: "zone1"}: 3,
					{key: "zone", value: "zone2"}: 2,
					{key: "zone", value: "zone3"}: 0,
				},
			},
		},
		{
			name: "namespace mismatch doesn't count",
			pod: st.MakePod().Name("p").Label("foo", "").SpreadConstraint(
				1, "zone", hardSpread, fooSelector,
			).Obj(),
			nodes: []*v1.Node{
				st.MakeNode().Name("node-a").Label("zone", "zone1").Label("node", "node-a").Obj(),
				st.MakeNode().Name("node-b").Label("zone", "zone1").Label("node", "node-b").Obj(),
				st.MakeNode().Name("node-x").Label("zone", "zone2").Label("node", "node-x").Obj(),
				st.MakeNode().Name("node-y").Label("zone", "zone2").Label("node", "node-y").Obj(),
			},
			existingPods: []*v1.Pod{
				st.MakePod().Name("p-a1").Node("node-a").Label("foo", "").Obj(),
				st.MakePod().Name("p-a2").Namespace("ns1").Node("node-a").Label("foo", "").Obj(),
				st.MakePod().Name("p-b1").Node("node-b").Label("foo", "").Obj(),
				st.MakePod().Name("p-y1").Namespace("ns2").Node("node-y").Label("foo", "").Obj(),
				st.MakePod().Name("p-y2").Node("node-y").Label("foo", "").Obj(),
			},
			want: &PodTopologySpreadMetadata{
				constraints: []topologySpreadConstraint{
					{
						maxSkew:     1,
						topologyKey: "zone",
						selector:    mustConvertLabelSelectorAsSelector(t, fooSelector),
					},
				},
				tpKeyToCriticalPaths: map[string]*criticalPaths{
					"zone": {{"zone2", 1}, {"zone1", 2}},
				},
				tpPairToMatchNum: map[topologyPair]int32{
					{key: "zone", value: "zone1"}: 2,
					{key: "zone", value: "zone2"}: 1,
				},
			},
		},
		{
			name: "normal case with two spreadConstraints",
			pod: st.MakePod().Name("p").Label("foo", "").
				SpreadConstraint(1, "zone", hardSpread, fooSelector).
				SpreadConstraint(1, "node", hardSpread, fooSelector).
				Obj(),
			nodes: []*v1.Node{
				st.MakeNode().Name("node-a").Label("zone", "zone1").Label("node", "node-a").Obj(),
				st.MakeNode().Name("node-b").Label("zone", "zone1").Label("node", "node-b").Obj(),
				st.MakeNode().Name("node-x").Label("zone", "zone2").Label("node", "node-x").Obj(),
				st.MakeNode().Name("node-y").Label("zone", "zone2").Label("node", "node-y").Obj(),
			},
			existingPods: []*v1.Pod{
				st.MakePod().Name("p-a1").Node("node-a").Label("foo", "").Obj(),
				st.MakePod().Name("p-a2").Node("node-a").Label("foo", "").Obj(),
				st.MakePod().Name("p-b1").Node("node-b").Label("foo", "").Obj(),
				st.MakePod().Name("p-y1").Node("node-y").Label("foo", "").Obj(),
				st.MakePod().Name("p-y2").Node("node-y").Label("foo", "").Obj(),
				st.MakePod().Name("p-y3").Node("node-y").Label("foo", "").Obj(),
				st.MakePod().Name("p-y4").Node("node-y").Label("foo", "").Obj(),
			},
			want: &PodTopologySpreadMetadata{
				constraints: []topologySpreadConstraint{
					{
						maxSkew:     1,
						topologyKey: "zone",
						selector:    mustConvertLabelSelectorAsSelector(t, fooSelector),
					},
					{
						maxSkew:     1,
						topologyKey: "node",
						selector:    mustConvertLabelSelectorAsSelector(t, fooSelector),
					},
				},
				tpKeyToCriticalPaths: map[string]*criticalPaths{
					"zone": {{"zone1", 3}, {"zone2", 4}},
					"node": {{"node-x", 0}, {"node-b", 1}},
				},
				tpPairToMatchNum: map[topologyPair]int32{
					{key: "zone", value: "zone1"}:  3,
					{key: "zone", value: "zone2"}:  4,
					{key: "node", value: "node-a"}: 2,
					{key: "node", value: "node-b"}: 1,
					{key: "node", value: "node-x"}: 0,
					{key: "node", value: "node-y"}: 4,
				},
			},
		},
		{
			name: "soft spreadConstraints should be bypassed",
			pod: st.MakePod().Name("p").Label("foo", "").
				SpreadConstraint(1, "zone", softSpread, fooSelector).
				SpreadConstraint(1, "zone", hardSpread, fooSelector).
				SpreadConstraint(1, "node", softSpread, fooSelector).
				SpreadConstraint(1, "node", hardSpread, fooSelector).
				Obj(),
			nodes: []*v1.Node{
				st.MakeNode().Name("node-a").Label("zone", "zone1").Label("node", "node-a").Obj(),
				st.MakeNode().Name("node-b").Label("zone", "zone1").Label("node", "node-b").Obj(),
				st.MakeNode().Name("node-y").Label("zone", "zone2").Label("node", "node-y").Obj(),
			},
			existingPods: []*v1.Pod{
				st.MakePod().Name("p-a1").Node("node-a").Label("foo", "").Obj(),
				st.MakePod().Name("p-a2").Node("node-a").Label("foo", "").Obj(),
				st.MakePod().Name("p-b1").Node("node-b").Label("foo", "").Obj(),
				st.MakePod().Name("p-y1").Node("node-y").Label("foo", "").Obj(),
				st.MakePod().Name("p-y2").Node("node-y").Label("foo", "").Obj(),
				st.MakePod().Name("p-y3").Node("node-y").Label("foo", "").Obj(),
				st.MakePod().Name("p-y4").Node("node-y").Label("foo", "").Obj(),
			},
			want: &PodTopologySpreadMetadata{
				constraints: []topologySpreadConstraint{
					{
						maxSkew:     1,
						topologyKey: "zone",
						selector:    mustConvertLabelSelectorAsSelector(t, fooSelector),
					},
					{
						maxSkew:     1,
						topologyKey: "node",
						selector:    mustConvertLabelSelectorAsSelector(t, fooSelector),
					},
				},
				tpKeyToCriticalPaths: map[string]*criticalPaths{
					"zone": {{"zone1", 3}, {"zone2", 4}},
					"node": {{"node-b", 1}, {"node-a", 2}},
				},
				tpPairToMatchNum: map[topologyPair]int32{
					{key: "zone", value: "zone1"}:  3,
					{key: "zone", value: "zone2"}:  4,
					{key: "node", value: "node-a"}: 2,
					{key: "node", value: "node-b"}: 1,
					{key: "node", value: "node-y"}: 4,
				},
			},
		},
		{
			name: "different labelSelectors - simple version",
			pod: st.MakePod().Name("p").Label("foo", "").Label("bar", "").
				SpreadConstraint(1, "zone", hardSpread, fooSelector).
				SpreadConstraint(1, "node", hardSpread, barSelector).
				Obj(),
			nodes: []*v1.Node{
				st.MakeNode().Name("node-a").Label("zone", "zone1").Label("node", "node-a").Obj(),
				st.MakeNode().Name("node-b").Label("zone", "zone1").Label("node", "node-b").Obj(),
				st.MakeNode().Name("node-y").Label("zone", "zone2").Label("node", "node-y").Obj(),
			},
			existingPods: []*v1.Pod{
				st.MakePod().Name("p-a").Node("node-a").Label("foo", "").Obj(),
				st.MakePod().Name("p-b").Node("node-b").Label("bar", "").Obj(),
			},
			want: &PodTopologySpreadMetadata{
				constraints: []topologySpreadConstraint{
					{
						maxSkew:     1,
						topologyKey: "zone",
						selector:    mustConvertLabelSelectorAsSelector(t, fooSelector),
					},
					{
						maxSkew:     1,
						topologyKey: "node",
						selector:    mustConvertLabelSelectorAsSelector(t, barSelector),
					},
				},
				tpKeyToCriticalPaths: map[string]*criticalPaths{
					"zone": {{"zone2", 0}, {"zone1", 1}},
					"node": {{"node-a", 0}, {"node-y", 0}},
				},
				tpPairToMatchNum: map[topologyPair]int32{
					{key: "zone", value: "zone1"}:  1,
					{key: "zone", value: "zone2"}:  0,
					{key: "node", value: "node-a"}: 0,
					{key: "node", value: "node-b"}: 1,
					{key: "node", value: "node-y"}: 0,
				},
			},
		},
		{
			name: "different labelSelectors - complex pods",
			pod: st.MakePod().Name("p").Label("foo", "").Label("bar", "").
				SpreadConstraint(1, "zone", hardSpread, fooSelector).
				SpreadConstraint(1, "node", hardSpread, barSelector).
				Obj(),
			nodes: []*v1.Node{
				st.MakeNode().Name("node-a").Label("zone", "zone1").Label("node", "node-a").Obj(),
				st.MakeNode().Name("node-b").Label("zone", "zone1").Label("node", "node-b").Obj(),
				st.MakeNode().Name("node-y").Label("zone", "zone2").Label("node", "node-y").Obj(),
			},
			existingPods: []*v1.Pod{
				st.MakePod().Name("p-a1").Node("node-a").Label("foo", "").Obj(),
				st.MakePod().Name("p-a2").Node("node-a").Label("foo", "").Label("bar", "").Obj(),
				st.MakePod().Name("p-b1").Node("node-b").Label("foo", "").Obj(),
				st.MakePod().Name("p-y1").Node("node-y").Label("foo", "").Obj(),
				st.MakePod().Name("p-y2").Node("node-y").Label("foo", "").Label("bar", "").Obj(),
				st.MakePod().Name("p-y3").Node("node-y").Label("foo", "").Obj(),
				st.MakePod().Name("p-y4").Node("node-y").Label("foo", "").Label("bar", "").Obj(),
			},
			want: &PodTopologySpreadMetadata{
				constraints: []topologySpreadConstraint{
					{
						maxSkew:     1,
						topologyKey: "zone",
						selector:    mustConvertLabelSelectorAsSelector(t, fooSelector),
					},
					{
						maxSkew:     1,
						topologyKey: "node",
						selector:    mustConvertLabelSelectorAsSelector(t, barSelector),
					},
				},
				tpKeyToCriticalPaths: map[string]*criticalPaths{
					"zone": {{"zone1", 3}, {"zone2", 4}},
					"node": {{"node-b", 0}, {"node-a", 1}},
				},
				tpPairToMatchNum: map[topologyPair]int32{
					{key: "zone", value: "zone1"}:  3,
					{key: "zone", value: "zone2"}:  4,
					{key: "node", value: "node-a"}: 1,
					{key: "node", value: "node-b"}: 0,
					{key: "node", value: "node-y"}: 2,
				},
			},
		},
		{
			name: "two spreadConstraints, and with podAffinity",
			pod: st.MakePod().Name("p").Label("foo", "").
				NodeAffinityNotIn("node", []string{"node-x"}). // exclude node-x
				SpreadConstraint(1, "zone", hardSpread, fooSelector).
				SpreadConstraint(1, "node", hardSpread, fooSelector).
				Obj(),
			nodes: []*v1.Node{
				st.MakeNode().Name("node-a").Label("zone", "zone1").Label("node", "node-a").Obj(),
				st.MakeNode().Name("node-b").Label("zone", "zone1").Label("node", "node-b").Obj(),
				st.MakeNode().Name("node-x").Label("zone", "zone2").Label("node", "node-x").Obj(),
				st.MakeNode().Name("node-y").Label("zone", "zone2").Label("node", "node-y").Obj(),
			},
			existingPods: []*v1.Pod{
				st.MakePod().Name("p-a1").Node("node-a").Label("foo", "").Obj(),
				st.MakePod().Name("p-a2").Node("node-a").Label("foo", "").Obj(),
				st.MakePod().Name("p-b1").Node("node-b").Label("foo", "").Obj(),
				st.MakePod().Name("p-y1").Node("node-y").Label("foo", "").Obj(),
				st.MakePod().Name("p-y2").Node("node-y").Label("foo", "").Obj(),
				st.MakePod().Name("p-y3").Node("node-y").Label("foo", "").Obj(),
				st.MakePod().Name("p-y4").Node("node-y").Label("foo", "").Obj(),
			},
			want: &PodTopologySpreadMetadata{
				constraints: []topologySpreadConstraint{
					{
						maxSkew:     1,
						topologyKey: "zone",
						selector:    mustConvertLabelSelectorAsSelector(t, fooSelector),
					},
					{
						maxSkew:     1,
						topologyKey: "node",
						selector:    mustConvertLabelSelectorAsSelector(t, fooSelector),
					},
				},
				tpKeyToCriticalPaths: map[string]*criticalPaths{
					"zone": {{"zone1", 3}, {"zone2", 4}},
					"node": {{"node-b", 1}, {"node-a", 2}},
				},
				tpPairToMatchNum: map[topologyPair]int32{
					{key: "zone", value: "zone1"}:  3,
					{key: "zone", value: "zone2"}:  4,
					{key: "node", value: "node-a"}: 2,
					{key: "node", value: "node-b"}: 1,
					{key: "node", value: "node-y"}: 4,
				},
			},
		},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			s := nodeinfosnapshot.NewSnapshot(nodeinfosnapshot.CreateNodeInfoMap(tt.existingPods, tt.nodes))
			l, _ := s.NodeInfos().List()
			got, _ := GetPodTopologySpreadMetadata(tt.pod, l)
			got.sortCriticalPaths()
			if !reflect.DeepEqual(got, tt.want) {
				t.Errorf("getEvenPodsSpreadMetadata() = %#v, want %#v", *got, *tt.want)
			}
		})
	}
}

func TestPodSpreadCache_addPod(t *testing.T) {
	nodeConstraint := topologySpreadConstraint{
		maxSkew:     1,
		topologyKey: "node",
		selector:    mustConvertLabelSelectorAsSelector(t, st.MakeLabelSelector().Exists("foo").Obj()),
	}
	zoneConstraint := nodeConstraint
	zoneConstraint.topologyKey = "zone"
	tests := []struct {
		name         string
		preemptor    *v1.Pod
		addedPod     *v1.Pod
		existingPods []*v1.Pod
		nodeIdx      int // denotes which node 'addedPod' belongs to
		nodes        []*v1.Node
		want         *PodTopologySpreadMetadata
	}{
		{
			name: "node a and b both impact current min match",
			preemptor: st.MakePod().Name("p").Label("foo", "").
				SpreadConstraint(1, "node", hardSpread, st.MakeLabelSelector().Exists("foo").Obj()).
				Obj(),
			addedPod:     st.MakePod().Name("p-a1").Node("node-a").Label("foo", "").Obj(),
			existingPods: nil, // it's an empty cluster
			nodeIdx:      0,
			nodes: []*v1.Node{
				st.MakeNode().Name("node-a").Label("zone", "zone1").Label("node", "node-a").Obj(),
				st.MakeNode().Name("node-b").Label("zone", "zone1").Label("node", "node-b").Obj(),
			},
			want: &PodTopologySpreadMetadata{
				constraints: []topologySpreadConstraint{nodeConstraint},
				tpKeyToCriticalPaths: map[string]*criticalPaths{
					"node": {{"node-b", 0}, {"node-a", 1}},
				},
				tpPairToMatchNum: map[topologyPair]int32{
					{key: "node", value: "node-a"}: 1,
					{key: "node", value: "node-b"}: 0,
				},
			},
		},
		{
			name: "only node a impacts current min match",
			preemptor: st.MakePod().Name("p").Label("foo", "").
				SpreadConstraint(1, "node", hardSpread, st.MakeLabelSelector().Exists("foo").Obj()).
				Obj(),
			addedPod: st.MakePod().Name("p-a1").Node("node-a").Label("foo", "").Obj(),
			existingPods: []*v1.Pod{
				st.MakePod().Name("p-b1").Node("node-b").Label("foo", "").Obj(),
			},
			nodeIdx: 0,
			nodes: []*v1.Node{
				st.MakeNode().Name("node-a").Label("zone", "zone1").Label("node", "node-a").Obj(),
				st.MakeNode().Name("node-b").Label("zone", "zone1").Label("node", "node-b").Obj(),
			},
			want: &PodTopologySpreadMetadata{
				constraints: []topologySpreadConstraint{nodeConstraint},
				tpKeyToCriticalPaths: map[string]*criticalPaths{
					"node": {{"node-a", 1}, {"node-b", 1}},
				},
				tpPairToMatchNum: map[topologyPair]int32{
					{key: "node", value: "node-a"}: 1,
					{key: "node", value: "node-b"}: 1,
				},
			},
		},
		{
			name: "add a pod with mis-matched namespace doesn't change topologyKeyToMinPodsMap",
			preemptor: st.MakePod().Name("p").Label("foo", "").
				SpreadConstraint(1, "node", hardSpread, st.MakeLabelSelector().Exists("foo").Obj()).
				Obj(),
			addedPod: st.MakePod().Name("p-a1").Namespace("ns1").Node("node-a").Label("foo", "").Obj(),
			existingPods: []*v1.Pod{
				st.MakePod().Name("p-b1").Node("node-b").Label("foo", "").Obj(),
			},
			nodeIdx: 0,
			nodes: []*v1.Node{
				st.MakeNode().Name("node-a").Label("zone", "zone1").Label("node", "node-a").Obj(),
				st.MakeNode().Name("node-b").Label("zone", "zone1").Label("node", "node-b").Obj(),
			},
			want: &PodTopologySpreadMetadata{
				constraints: []topologySpreadConstraint{nodeConstraint},
				tpKeyToCriticalPaths: map[string]*criticalPaths{
					"node": {{"node-a", 0}, {"node-b", 1}},
				},
				tpPairToMatchNum: map[topologyPair]int32{
					{key: "node", value: "node-a"}: 0,
					{key: "node", value: "node-b"}: 1,
				},
			},
		},
		{
			name: "add pod on non-critical node won't trigger re-calculation",
			preemptor: st.MakePod().Name("p").Label("foo", "").
				SpreadConstraint(1, "node", hardSpread, st.MakeLabelSelector().Exists("foo").Obj()).
				Obj(),
			addedPod: st.MakePod().Name("p-b2").Node("node-b").Label("foo", "").Obj(),
			existingPods: []*v1.Pod{
				st.MakePod().Name("p-b1").Node("node-b").Label("foo", "").Obj(),
			},
			nodeIdx: 1,
			nodes: []*v1.Node{
				st.MakeNode().Name("node-a").Label("zone", "zone1").Label("node", "node-a").Obj(),
				st.MakeNode().Name("node-b").Label("zone", "zone1").Label("node", "node-b").Obj(),
			},
			want: &PodTopologySpreadMetadata{
				constraints: []topologySpreadConstraint{nodeConstraint},
				tpKeyToCriticalPaths: map[string]*criticalPaths{
					"node": {{"node-a", 0}, {"node-b", 2}},
				},
				tpPairToMatchNum: map[topologyPair]int32{
					{key: "node", value: "node-a"}: 0,
					{key: "node", value: "node-b"}: 2,
				},
			},
		},
		{
			name: "node a and x both impact topologyKeyToMinPodsMap on zone and node",
			preemptor: st.MakePod().Name("p").Label("foo", "").
				SpreadConstraint(1, "zone", hardSpread, st.MakeLabelSelector().Exists("foo").Obj()).
				SpreadConstraint(1, "node", hardSpread, st.MakeLabelSelector().Exists("foo").Obj()).
				Obj(),
			addedPod:     st.MakePod().Name("p-a1").Node("node-a").Label("foo", "").Obj(),
			existingPods: nil, // it's an empty cluster
			nodeIdx:      0,
			nodes: []*v1.Node{
				st.MakeNode().Name("node-a").Label("zone", "zone1").Label("node", "node-a").Obj(),
				st.MakeNode().Name("node-x").Label("zone", "zone2").Label("node", "node-x").Obj(),
			},
			want: &PodTopologySpreadMetadata{
				constraints: []topologySpreadConstraint{zoneConstraint, nodeConstraint},
				tpKeyToCriticalPaths: map[string]*criticalPaths{
					"zone": {{"zone2", 0}, {"zone1", 1}},
					"node": {{"node-x", 0}, {"node-a", 1}},
				},
				tpPairToMatchNum: map[topologyPair]int32{
					{key: "zone", value: "zone1"}:  1,
					{key: "zone", value: "zone2"}:  0,
					{key: "node", value: "node-a"}: 1,
					{key: "node", value: "node-x"}: 0,
				},
			},
		},
		{
			name: "only node a impacts topologyKeyToMinPodsMap on zone and node",
			preemptor: st.MakePod().Name("p").Label("foo", "").
				SpreadConstraint(1, "zone", hardSpread, st.MakeLabelSelector().Exists("foo").Obj()).
				SpreadConstraint(1, "node", hardSpread, st.MakeLabelSelector().Exists("foo").Obj()).
				Obj(),
			addedPod: st.MakePod().Name("p-a1").Node("node-a").Label("foo", "").Obj(),
			existingPods: []*v1.Pod{
				st.MakePod().Name("p-x1").Node("node-x").Label("foo", "").Obj(),
			},
			nodeIdx: 0,
			nodes: []*v1.Node{
				st.MakeNode().Name("node-a").Label("zone", "zone1").Label("node", "node-a").Obj(),
				st.MakeNode().Name("node-x").Label("zone", "zone2").Label("node", "node-x").Obj(),
			},
			want: &PodTopologySpreadMetadata{
				constraints: []topologySpreadConstraint{zoneConstraint, nodeConstraint},
				tpKeyToCriticalPaths: map[string]*criticalPaths{
					"zone": {{"zone1", 1}, {"zone2", 1}},
					"node": {{"node-a", 1}, {"node-x", 1}},
				},
				tpPairToMatchNum: map[topologyPair]int32{
					{key: "zone", value: "zone1"}:  1,
					{key: "zone", value: "zone2"}:  1,
					{key: "node", value: "node-a"}: 1,
					{key: "node", value: "node-x"}: 1,
				},
			},
		},
		{
			name: "node a impacts topologyKeyToMinPodsMap on node, node x impacts topologyKeyToMinPodsMap on zone",
			preemptor: st.MakePod().Name("p").Label("foo", "").
				SpreadConstraint(1, "zone", hardSpread, st.MakeLabelSelector().Exists("foo").Obj()).
				SpreadConstraint(1, "node", hardSpread, st.MakeLabelSelector().Exists("foo").Obj()).
				Obj(),
			addedPod: st.MakePod().Name("p-a1").Node("node-a").Label("foo", "").Obj(),
			existingPods: []*v1.Pod{
				st.MakePod().Name("p-b1").Node("node-b").Label("foo", "").Obj(),
				st.MakePod().Name("p-b2").Node("node-b").Label("foo", "").Obj(),
				st.MakePod().Name("p-x1").Node("node-x").Label("foo", "").Obj(),
			},
			nodeIdx: 0,
			nodes: []*v1.Node{
				st.MakeNode().Name("node-a").Label("zone", "zone1").Label("node", "node-a").Obj(),
				st.MakeNode().Name("node-b").Label("zone", "zone1").Label("node", "node-b").Obj(),
				st.MakeNode().Name("node-x").Label("zone", "zone2").Label("node", "node-x").Obj(),
			},
			want: &PodTopologySpreadMetadata{
				constraints: []topologySpreadConstraint{zoneConstraint, nodeConstraint},
				tpKeyToCriticalPaths: map[string]*criticalPaths{
					"zone": {{"zone2", 1}, {"zone1", 3}},
					"node": {{"node-a", 1}, {"node-x", 1}},
				},
				tpPairToMatchNum: map[topologyPair]int32{
					{key: "zone", value: "zone1"}:  3,
					{key: "zone", value: "zone2"}:  1,
					{key: "node", value: "node-a"}: 1,
					{key: "node", value: "node-b"}: 2,
					{key: "node", value: "node-x"}: 1,
				},
			},
		},
		{
			name: "constraints hold different labelSelectors, node a impacts topologyKeyToMinPodsMap on zone",
			preemptor: st.MakePod().Name("p").Label("foo", "").Label("bar", "").
				SpreadConstraint(1, "zone", hardSpread, st.MakeLabelSelector().Exists("foo").Obj()).
				SpreadConstraint(1, "node", hardSpread, st.MakeLabelSelector().Exists("bar").Obj()).
				Obj(),
			addedPod: st.MakePod().Name("p-a1").Node("node-a").Label("foo", "").Obj(),
			existingPods: []*v1.Pod{
				st.MakePod().Name("p-b1").Node("node-b").Label("foo", "").Label("bar", "").Obj(),
				st.MakePod().Name("p-x1").Node("node-x").Label("foo", "").Label("bar", "").Obj(),
				st.MakePod().Name("p-x2").Node("node-x").Label("bar", "").Obj(),
			},
			nodeIdx: 0,
			nodes: []*v1.Node{
				st.MakeNode().Name("node-a").Label("zone", "zone1").Label("node", "node-a").Obj(),
				st.MakeNode().Name("node-b").Label("zone", "zone1").Label("node", "node-b").Obj(),
				st.MakeNode().Name("node-x").Label("zone", "zone2").Label("node", "node-x").Obj(),
			},
			want: &PodTopologySpreadMetadata{
				constraints: []topologySpreadConstraint{
					zoneConstraint,
					{
						maxSkew:     1,
						topologyKey: "node",
						selector:    mustConvertLabelSelectorAsSelector(t, st.MakeLabelSelector().Exists("bar").Obj()),
					},
				},
				tpKeyToCriticalPaths: map[string]*criticalPaths{
					"zone": {{"zone2", 1}, {"zone1", 2}},
					"node": {{"node-a", 0}, {"node-b", 1}},
				},
				tpPairToMatchNum: map[topologyPair]int32{
					{key: "zone", value: "zone1"}:  2,
					{key: "zone", value: "zone2"}:  1,
					{key: "node", value: "node-a"}: 0,
					{key: "node", value: "node-b"}: 1,
					{key: "node", value: "node-x"}: 2,
				},
			},
		},
		{
			name: "constraints hold different labelSelectors, node a impacts topologyKeyToMinPodsMap on both zone and node",
			preemptor: st.MakePod().Name("p").Label("foo", "").Label("bar", "").
				SpreadConstraint(1, "zone", hardSpread, st.MakeLabelSelector().Exists("foo").Obj()).
				SpreadConstraint(1, "node", hardSpread, st.MakeLabelSelector().Exists("bar").Obj()).
				Obj(),
			addedPod: st.MakePod().Name("p-a1").Node("node-a").Label("foo", "").Label("bar", "").Obj(),
			existingPods: []*v1.Pod{
				st.MakePod().Name("p-b1").Node("node-b").Label("bar", "").Obj(),
				st.MakePod().Name("p-x1").Node("node-x").Label("foo", "").Label("bar", "").Obj(),
				st.MakePod().Name("p-x2").Node("node-x").Label("bar", "").Obj(),
			},
			nodeIdx: 0,
			nodes: []*v1.Node{
				st.MakeNode().Name("node-a").Label("zone", "zone1").Label("node", "node-a").Obj(),
				st.MakeNode().Name("node-b").Label("zone", "zone1").Label("node", "node-b").Obj(),
				st.MakeNode().Name("node-x").Label("zone", "zone2").Label("node", "node-x").Obj(),
			},
			want: &PodTopologySpreadMetadata{
				constraints: []topologySpreadConstraint{
					zoneConstraint,
					{
						maxSkew:     1,
						topologyKey: "node",
						selector:    mustConvertLabelSelectorAsSelector(t, st.MakeLabelSelector().Exists("bar").Obj()),
					},
				},
				tpKeyToCriticalPaths: map[string]*criticalPaths{
					"zone": {{"zone1", 1}, {"zone2", 1}},
					"node": {{"node-a", 1}, {"node-b", 1}},
				},
				tpPairToMatchNum: map[topologyPair]int32{
					{key: "zone", value: "zone1"}:  1,
					{key: "zone", value: "zone2"}:  1,
					{key: "node", value: "node-a"}: 1,
					{key: "node", value: "node-b"}: 1,
					{key: "node", value: "node-x"}: 2,
				},
			},
		},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			s := nodeinfosnapshot.NewSnapshot(nodeinfosnapshot.CreateNodeInfoMap(tt.existingPods, tt.nodes))
			l, _ := s.NodeInfos().List()
			podTopologySpreadMeta, _ := GetPodTopologySpreadMetadata(tt.preemptor, l)
			podTopologySpreadMeta.AddPod(tt.addedPod, tt.preemptor, tt.nodes[tt.nodeIdx])
			podTopologySpreadMeta.sortCriticalPaths()
			if !reflect.DeepEqual(podTopologySpreadMeta, tt.want) {
				t.Errorf("podTopologySpreadMeta#addPod() = %v, want %v", podTopologySpreadMeta, tt.want)
			}
		})
	}
}

func TestPodSpreadCache_removePod(t *testing.T) {
	nodeConstraint := topologySpreadConstraint{
		maxSkew:     1,
		topologyKey: "node",
		selector:    mustConvertLabelSelectorAsSelector(t, st.MakeLabelSelector().Exists("foo").Obj()),
	}
	zoneConstraint := nodeConstraint
	zoneConstraint.topologyKey = "zone"
	tests := []struct {
		name          string
		preemptor     *v1.Pod // preemptor pod
		nodes         []*v1.Node
		existingPods  []*v1.Pod
		deletedPodIdx int     // need to reuse *Pod of existingPods[i]
		deletedPod    *v1.Pod // this field is used only when deletedPodIdx is -1
		nodeIdx       int     // denotes which node "deletedPod" belongs to
		want          *PodTopologySpreadMetadata
	}{
		{
			// A high priority pod may not be scheduled due to node taints or resource shortage.
			// So preemption is triggered.
			name: "one spreadConstraint on zone, topologyKeyToMinPodsMap unchanged",
			preemptor: st.MakePod().Name("p").Label("foo", "").
				SpreadConstraint(1, "zone", hardSpread, st.MakeLabelSelector().Exists("foo").Obj()).
				Obj(),
			nodes: []*v1.Node{
				st.MakeNode().Name("node-a").Label("zone", "zone1").Label("node", "node-a").Obj(),
				st.MakeNode().Name("node-b").Label("zone", "zone1").Label("node", "node-b").Obj(),
				st.MakeNode().Name("node-x").Label("zone", "zone2").Label("node", "node-x").Obj(),
			},
			existingPods: []*v1.Pod{
				st.MakePod().Name("p-a1").Node("node-a").Label("foo", "").Obj(),
				st.MakePod().Name("p-b1").Node("node-b").Label("foo", "").Obj(),
				st.MakePod().Name("p-x1").Node("node-x").Label("foo", "").Obj(),
			},
			deletedPodIdx: 0, // remove pod "p-a1"
			nodeIdx:       0, // node-a
			want: &PodTopologySpreadMetadata{
				constraints: []topologySpreadConstraint{zoneConstraint},
				tpKeyToCriticalPaths: map[string]*criticalPaths{
					"zone": {{"zone1", 1}, {"zone2", 1}},
				},
				tpPairToMatchNum: map[topologyPair]int32{
					{key: "zone", value: "zone1"}: 1,
					{key: "zone", value: "zone2"}: 1,
				},
			},
		},
		{
			name: "one spreadConstraint on node, topologyKeyToMinPodsMap changed",
			preemptor: st.MakePod().Name("p").Label("foo", "").
				SpreadConstraint(1, "zone", hardSpread, st.MakeLabelSelector().Exists("foo").Obj()).
				Obj(),
			nodes: []*v1.Node{
				st.MakeNode().Name("node-a").Label("zone", "zone1").Label("node", "node-a").Obj(),
				st.MakeNode().Name("node-b").Label("zone", "zone1").Label("node", "node-b").Obj(),
				st.MakeNode().Name("node-x").Label("zone", "zone2").Label("node", "node-x").Obj(),
				st.MakeNode().Name("node-y").Label("zone", "zone2").Label("node", "node-y").Obj(),
			},
			existingPods: []*v1.Pod{
				st.MakePod().Name("p-a1").Node("node-a").Label("foo", "").Obj(),
				st.MakePod().Name("p-b1").Node("node-b").Label("foo", "").Obj(),
				st.MakePod().Name("p-x1").Node("node-x").Label("foo", "").Obj(),
				st.MakePod().Name("p-y1").Node("node-y").Label("foo", "").Obj(),
			},
			deletedPodIdx: 0, // remove pod "p-a1"
			nodeIdx:       0, // node-a
			want: &PodTopologySpreadMetadata{
				constraints: []topologySpreadConstraint{zoneConstraint},
				tpKeyToCriticalPaths: map[string]*criticalPaths{
					"zone": {{"zone1", 1}, {"zone2", 2}},
				},
				tpPairToMatchNum: map[topologyPair]int32{
					{key: "zone", value: "zone1"}: 1,
					{key: "zone", value: "zone2"}: 2,
				},
			},
		},
		{
			name: "delete an irrelevant pod won't help",
			preemptor: st.MakePod().Name("p").Label("foo", "").
				SpreadConstraint(1, "zone", hardSpread, st.MakeLabelSelector().Exists("foo").Obj()).
				Obj(),
			nodes: []*v1.Node{
				st.MakeNode().Name("node-a").Label("zone", "zone1").Label("node", "node-a").Obj(),
				st.MakeNode().Name("node-b").Label("zone", "zone1").Label("node", "node-b").Obj(),
				st.MakeNode().Name("node-x").Label("zone", "zone2").Label("node", "node-x").Obj(),
				st.MakeNode().Name("node-y").Label("zone", "zone2").Label("node", "node-y").Obj(),
			},
			existingPods: []*v1.Pod{
				st.MakePod().Name("p-a0").Node("node-a").Label("bar", "").Obj(),
				st.MakePod().Name("p-a1").Node("node-a").Label("foo", "").Obj(),
				st.MakePod().Name("p-b1").Node("node-b").Label("foo", "").Obj(),
				st.MakePod().Name("p-x1").Node("node-x").Label("foo", "").Obj(),
				st.MakePod().Name("p-y1").Node("node-y").Label("foo", "").Obj(),
			},
			deletedPodIdx: 0, // remove pod "p-a0"
			nodeIdx:       0, // node-a
			want: &PodTopologySpreadMetadata{
				constraints: []topologySpreadConstraint{zoneConstraint},
				tpKeyToCriticalPaths: map[string]*criticalPaths{
					"zone": {{"zone1", 2}, {"zone2", 2}},
				},
				tpPairToMatchNum: map[topologyPair]int32{
					{key: "zone", value: "zone1"}: 2,
					{key: "zone", value: "zone2"}: 2,
				},
			},
		},
		{
			name: "delete a non-existing pod won't help",
			preemptor: st.MakePod().Name("p").Label("foo", "").
				SpreadConstraint(1, "zone", hardSpread, st.MakeLabelSelector().Exists("foo").Obj()).
				Obj(),
			nodes: []*v1.Node{
				st.MakeNode().Name("node-a").Label("zone", "zone1").Label("node", "node-a").Obj(),
				st.MakeNode().Name("node-b").Label("zone", "zone1").Label("node", "node-b").Obj(),
				st.MakeNode().Name("node-x").Label("zone", "zone2").Label("node", "node-x").Obj(),
				st.MakeNode().Name("node-y").Label("zone", "zone2").Label("node", "node-y").Obj(),
			},
			existingPods: []*v1.Pod{
				st.MakePod().Name("p-a1").Node("node-a").Label("foo", "").Obj(),
				st.MakePod().Name("p-b1").Node("node-b").Label("foo", "").Obj(),
				st.MakePod().Name("p-x1").Node("node-x").Label("foo", "").Obj(),
				st.MakePod().Name("p-y1").Node("node-y").Label("foo", "").Obj(),
			},
			deletedPodIdx: -1,
			deletedPod:    st.MakePod().Name("p-a0").Node("node-a").Label("bar", "").Obj(),
			nodeIdx:       0, // node-a
			want: &PodTopologySpreadMetadata{
				constraints: []topologySpreadConstraint{zoneConstraint},
				tpKeyToCriticalPaths: map[string]*criticalPaths{
					"zone": {{"zone1", 2}, {"zone2", 2}},
				},
				tpPairToMatchNum: map[topologyPair]int32{
					{key: "zone", value: "zone1"}: 2,
					{key: "zone", value: "zone2"}: 2,
				},
			},
		},
		{
			name: "two spreadConstraints",
			preemptor: st.MakePod().Name("p").Label("foo", "").
				SpreadConstraint(1, "zone", hardSpread, st.MakeLabelSelector().Exists("foo").Obj()).
				SpreadConstraint(1, "node", hardSpread, st.MakeLabelSelector().Exists("foo").Obj()).
				Obj(),
			nodes: []*v1.Node{
				st.MakeNode().Name("node-a").Label("zone", "zone1").Label("node", "node-a").Obj(),
				st.MakeNode().Name("node-b").Label("zone", "zone1").Label("node", "node-b").Obj(),
				st.MakeNode().Name("node-x").Label("zone", "zone2").Label("node", "node-x").Obj(),
			},
			existingPods: []*v1.Pod{
				st.MakePod().Name("p-a1").Node("node-a").Label("foo", "").Obj(),
				st.MakePod().Name("p-a2").Node("node-a").Label("foo", "").Obj(),
				st.MakePod().Name("p-b1").Node("node-b").Label("foo", "").Obj(),
				st.MakePod().Name("p-x1").Node("node-x").Label("foo", "").Obj(),
				st.MakePod().Name("p-x2").Node("node-x").Label("foo", "").Obj(),
			},
			deletedPodIdx: 3, // remove pod "p-x1"
			nodeIdx:       2, // node-x
			want: &PodTopologySpreadMetadata{
				constraints: []topologySpreadConstraint{zoneConstraint, nodeConstraint},
				tpKeyToCriticalPaths: map[string]*criticalPaths{
					"zone": {{"zone2", 1}, {"zone1", 3}},
					"node": {{"node-b", 1}, {"node-x", 1}},
				},
				tpPairToMatchNum: map[topologyPair]int32{
					{key: "zone", value: "zone1"}:  3,
					{key: "zone", value: "zone2"}:  1,
					{key: "node", value: "node-a"}: 2,
					{key: "node", value: "node-b"}: 1,
					{key: "node", value: "node-x"}: 1,
				},
			},
		},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			s := nodeinfosnapshot.NewSnapshot(nodeinfosnapshot.CreateNodeInfoMap(tt.existingPods, tt.nodes))
			l, _ := s.NodeInfos().List()
			podTopologySpreadMeta, _ := GetPodTopologySpreadMetadata(tt.preemptor, l)

			var deletedPod *v1.Pod
			if tt.deletedPodIdx < len(tt.existingPods) && tt.deletedPodIdx >= 0 {
				deletedPod = tt.existingPods[tt.deletedPodIdx]
			} else {
				deletedPod = tt.deletedPod
			}
			podTopologySpreadMeta.RemovePod(deletedPod, tt.preemptor, tt.nodes[tt.nodeIdx])
			podTopologySpreadMeta.sortCriticalPaths()
			if !reflect.DeepEqual(podTopologySpreadMeta, tt.want) {
				t.Errorf("podTopologySpreadMeta#removePod() = %v, want %v", podTopologySpreadMeta, tt.want)
			}
		})
	}
}

func BenchmarkTestGetTPMapMatchingSpreadConstraints(b *testing.B) {
	tests := []struct {
		name             string
		pod              *v1.Pod
		existingPodsNum  int
		allNodesNum      int
		filteredNodesNum int
	}{
		{
			name: "1000nodes/single-constraint-zone",
			pod: st.MakePod().Name("p").Label("foo", "").
				SpreadConstraint(1, v1.LabelZoneFailureDomain, hardSpread, st.MakeLabelSelector().Exists("foo").Obj()).
				Obj(),
			existingPodsNum:  10000,
			allNodesNum:      1000,
			filteredNodesNum: 500,
		},
		{
			name: "1000nodes/single-constraint-node",
			pod: st.MakePod().Name("p").Label("foo", "").
				SpreadConstraint(1, v1.LabelHostname, hardSpread, st.MakeLabelSelector().Exists("foo").Obj()).
				Obj(),
			existingPodsNum:  10000,
			allNodesNum:      1000,
			filteredNodesNum: 500,
		},
		{
			name: "1000nodes/two-constraints-zone-node",
			pod: st.MakePod().Name("p").Label("foo", "").Label("bar", "").
				SpreadConstraint(1, v1.LabelZoneFailureDomain, hardSpread, st.MakeLabelSelector().Exists("foo").Obj()).
				SpreadConstraint(1, v1.LabelHostname, hardSpread, st.MakeLabelSelector().Exists("bar").Obj()).
				Obj(),
			existingPodsNum:  10000,
			allNodesNum:      1000,
			filteredNodesNum: 500,
		},
	}
	for _, tt := range tests {
		b.Run(tt.name, func(b *testing.B) {
			existingPods, allNodes, _ := st.MakeNodesAndPodsForEvenPodsSpread(tt.pod.Labels, tt.existingPodsNum, tt.allNodesNum, tt.filteredNodesNum)
			s := nodeinfosnapshot.NewSnapshot(nodeinfosnapshot.CreateNodeInfoMap(existingPods, allNodes))
			l, _ := s.NodeInfos().List()
			b.ResetTimer()
			for i := 0; i < b.N; i++ {
				GetPodTopologySpreadMetadata(tt.pod, l)
			}
		})
	}
}

var (
	hardSpread = v1.DoNotSchedule
	softSpread = v1.ScheduleAnyway
)

// sortCriticalPaths is only served for testing purpose.
func (m *PodTopologySpreadMetadata) sortCriticalPaths() {
	for _, paths := range m.tpKeyToCriticalPaths {
		// If two paths both hold minimum matching number, and topologyValue is unordered.
		if paths[0].matchNum == paths[1].matchNum && paths[0].topologyValue > paths[1].topologyValue {
			// Swap topologyValue to make them sorted alphabetically.
			paths[0].topologyValue, paths[1].topologyValue = paths[1].topologyValue, paths[0].topologyValue
		}
	}
}

func mustConvertLabelSelectorAsSelector(t *testing.T, ls *metav1.LabelSelector) labels.Selector {
	t.Helper()
	s, err := metav1.LabelSelectorAsSelector(ls)
	if err != nil {
		t.Fatal(err)
	}
	return s
}