open-nomad/scheduler/feasible_test.go

package scheduler

import (
	"fmt"
	"reflect"
	"testing"

	"github.com/hashicorp/nomad/nomad/mock"
	"github.com/hashicorp/nomad/nomad/structs"
)

func TestStaticIterator_Reset(t *testing.T) {
	_, ctx := testContext(t)
	var nodes []*structs.Node
	for i := 0; i < 3; i++ {
		nodes = append(nodes, mock.Node())
	}
	static := NewStaticIterator(ctx, nodes)

	for i := 0; i < 6; i++ {
		static.Reset()
		for j := 0; j < i; j++ {
			static.Next()
		}
		static.Reset()

		out := collectFeasible(static)
		if len(out) != len(nodes) {
			t.Fatalf("out: %#v", out)
			t.Fatalf("missing nodes %d %#v", i, static)
		}

		ids := make(map[string]struct{})
		for _, o := range out {
			if _, ok := ids[o.ID]; ok {
				t.Fatalf("duplicate")
			}
			ids[o.ID] = struct{}{}
		}
	}
}

func TestStaticIterator_SetNodes(t *testing.T) {
	_, ctx := testContext(t)
	var nodes []*structs.Node
	for i := 0; i < 3; i++ {
		nodes = append(nodes, mock.Node())
	}
	static := NewStaticIterator(ctx, nodes)

	newNodes := []*structs.Node{mock.Node()}
	static.SetNodes(newNodes)

	out := collectFeasible(static)
	if !reflect.DeepEqual(out, newNodes) {
		t.Fatalf("bad: %#v", out)
	}
}

func TestRandomIterator(t *testing.T) {
	_, ctx := testContext(t)
	var nodes []*structs.Node
	for i := 0; i < 10; i++ {
		nodes = append(nodes, mock.Node())
	}

	nc := make([]*structs.Node, len(nodes))
	copy(nc, nodes)
	rand := NewRandomIterator(ctx, nc)

	out := collectFeasible(rand)
	if len(out) != len(nodes) {
		t.Fatalf("missing nodes")
	}
	if reflect.DeepEqual(out, nodes) {
		t.Fatalf("same order")
	}
}

func TestDriverChecker(t *testing.T) {
	_, ctx := testContext(t)
	nodes := []*structs.Node{
		mock.Node(),
		mock.Node(),
		mock.Node(),
		mock.Node(),
	}
	nodes[0].Attributes["driver.foo"] = "1"
	nodes[1].Attributes["driver.foo"] = "0"
	nodes[2].Attributes["driver.foo"] = "true"
	nodes[3].Attributes["driver.foo"] = "False"

	drivers := map[string]struct{}{
		"exec": struct{}{},
		"foo":  struct{}{},
	}
	checker := NewDriverChecker(ctx, drivers)
	cases := []struct {
		Node   *structs.Node
		Result bool
	}{
		{
			Node:   nodes[0],
			Result: true,
		},
		{
			Node:   nodes[1],
			Result: false,
		},
		{
			Node:   nodes[2],
			Result: true,
		},
		{
			Node:   nodes[3],
			Result: false,
		},
	}

	for i, c := range cases {
		if act := checker.Feasible(c.Node); act != c.Result {
			t.Fatalf("case(%d) failed: got %v; want %v", i, act, c.Result)
		}
	}
}

func TestConstraintChecker(t *testing.T) {
	_, ctx := testContext(t)
	nodes := []*structs.Node{
		mock.Node(),
		mock.Node(),
		mock.Node(),
		mock.Node(),
	}

	nodes[0].Attributes["kernel.name"] = "freebsd"
	nodes[1].Datacenter = "dc2"
	nodes[2].NodeClass = "large"

	constraints := []*structs.Constraint{
		&structs.Constraint{
			Operand: "=",
			LTarget: "${node.datacenter}",
			RTarget: "dc1",
		},
		&structs.Constraint{
			Operand: "is",
			LTarget: "${attr.kernel.name}",
			RTarget: "linux",
		},
		&structs.Constraint{
			Operand: "is",
			LTarget: "${node.class}",
			RTarget: "large",
		},
	}
	checker := NewConstraintChecker(ctx, constraints)
	cases := []struct {
		Node   *structs.Node
		Result bool
	}{
		{
			Node:   nodes[0],
			Result: false,
		},
		{
			Node:   nodes[1],
			Result: false,
		},
		{
			Node:   nodes[2],
			Result: true,
		},
	}

	for i, c := range cases {
		if act := checker.Feasible(c.Node); act != c.Result {
			t.Fatalf("case(%d) failed: got %v; want %v", i, act, c.Result)
		}
	}
}

func TestResolveConstraintTarget(t *testing.T) {
	type tcase struct {
		target string
		node   *structs.Node
		val    interface{}
		result bool
	}
	node := mock.Node()
	cases := []tcase{
		{
			target: "${node.unique.id}",
			node:   node,
			val:    node.ID,
			result: true,
		},
		{
			target: "${node.datacenter}",
			node:   node,
			val:    node.Datacenter,
			result: true,
		},
		{
			target: "${node.unique.name}",
			node:   node,
			val:    node.Name,
			result: true,
		},
		{
			target: "${node.class}",
			node:   node,
			val:    node.NodeClass,
			result: true,
		},
		{
			target: "${node.foo}",
			node:   node,
			result: false,
		},
		{
			target: "${attr.kernel.name}",
			node:   node,
			val:    node.Attributes["kernel.name"],
			result: true,
		},
		{
			target: "${attr.rand}",
			node:   node,
			result: false,
		},
		{
			target: "${meta.pci-dss}",
			node:   node,
			val:    node.Meta["pci-dss"],
			result: true,
		},
		{
			target: "${meta.rand}",
			node:   node,
			result: false,
		},
	}

	for _, tc := range cases {
		res, ok := resolveConstraintTarget(tc.target, tc.node)
		if ok != tc.result {
			t.Fatalf("TC: %#v, Result: %v %v", tc, res, ok)
		}
		if ok && !reflect.DeepEqual(res, tc.val) {
			t.Fatalf("TC: %#v, Result: %v %v", tc, res, ok)
		}
	}
}

func TestCheckConstraint(t *testing.T) {
	type tcase struct {
		op         string
		lVal, rVal interface{}
		result     bool
	}
	cases := []tcase{
		{
			op:   "=",
			lVal: "foo", rVal: "foo",
			result: true,
		},
		{
			op:   "is",
			lVal: "foo", rVal: "foo",
			result: true,
		},
		{
			op:   "==",
			lVal: "foo", rVal: "foo",
			result: true,
		},
		{
			op:   "!=",
			lVal: "foo", rVal: "foo",
			result: false,
		},
		{
			op:   "!=",
			lVal: "foo", rVal: "bar",
			result: true,
		},
		{
			op:   "not",
			lVal: "foo", rVal: "bar",
			result: true,
		},
		{
			op:   structs.ConstraintVersion,
			lVal: "1.2.3", rVal: "~> 1.0",
			result: true,
		},
		{
			op:   structs.ConstraintRegex,
			lVal: "foobarbaz", rVal: "[\\w]+",
			result: true,
		},
		{
			op:   "<",
			lVal: "foo", rVal: "bar",
			result: false,
		},
		{
			op:   structs.ConstraintSetContains,
			lVal: "foo,bar,baz", rVal: "foo,  bar  ",
			result: true,
		},
		{
			op:   structs.ConstraintSetContains,
			lVal: "foo,bar,baz", rVal: "foo,bam",
			result: false,
		},
	}

	for _, tc := range cases {
		_, ctx := testContext(t)
		if res := checkConstraint(ctx, tc.op, tc.lVal, tc.rVal); res != tc.result {
			t.Fatalf("TC: %#v, Result: %v", tc, res)
		}
	}
}

func TestCheckLexicalOrder(t *testing.T) {
	type tcase struct {
		op         string
		lVal, rVal interface{}
		result     bool
	}
	cases := []tcase{
		{
			op:   "<",
			lVal: "bar", rVal: "foo",
			result: true,
		},
		{
			op:   "<=",
			lVal: "foo", rVal: "foo",
			result: true,
		},
		{
			op:   ">",
			lVal: "bar", rVal: "foo",
			result: false,
		},
		{
			op:   ">=",
			lVal: "bar", rVal: "bar",
			result: true,
		},
		{
			op:   ">",
			lVal: 1, rVal: "foo",
			result: false,
		},
	}
	for _, tc := range cases {
		if res := checkLexicalOrder(tc.op, tc.lVal, tc.rVal); res != tc.result {
			t.Fatalf("TC: %#v, Result: %v", tc, res)
		}
	}
}

func TestCheckVersionConstraint(t *testing.T) {
	type tcase struct {
		lVal, rVal interface{}
		result     bool
	}
	cases := []tcase{
		{
			lVal: "1.2.3", rVal: "~> 1.0",
			result: true,
		},
		{
			lVal: "1.2.3", rVal: ">= 1.0, < 1.4",
			result: true,
		},
		{
			lVal: "2.0.1", rVal: "~> 1.0",
			result: false,
		},
		{
			lVal: "1.4", rVal: ">= 1.0, < 1.4",
			result: false,
		},
		{
			lVal: 1, rVal: "~> 1.0",
			result: true,
		},
	}
	for _, tc := range cases {
		_, ctx := testContext(t)
		if res := checkVersionConstraint(ctx, tc.lVal, tc.rVal); res != tc.result {
			t.Fatalf("TC: %#v, Result: %v", tc, res)
		}
	}
}

func TestCheckRegexpConstraint(t *testing.T) {
	type tcase struct {
		lVal, rVal interface{}
		result     bool
	}
	cases := []tcase{
		{
			lVal: "foobar", rVal: "bar",
			result: true,
		},
		{
			lVal: "foobar", rVal: "^foo",
			result: true,
		},
		{
			lVal: "foobar", rVal: "^bar",
			result: false,
		},
		{
			lVal: "zipzap", rVal: "foo",
			result: false,
		},
		{
			lVal: 1, rVal: "foo",
			result: false,
		},
	}
	for _, tc := range cases {
		_, ctx := testContext(t)
		if res := checkRegexpConstraint(ctx, tc.lVal, tc.rVal); res != tc.result {
			t.Fatalf("TC: %#v, Result: %v", tc, res)
		}
	}
}

// This test puts allocations on the node to test if it detects infeasibility of
// nodes correctly and picks the only feasible one
func TestDistinctHostsIterator_JobDistinctHosts(t *testing.T) {
	_, ctx := testContext(t)
	nodes := []*structs.Node{
		mock.Node(),
		mock.Node(),
		mock.Node(),
	}
	static := NewStaticIterator(ctx, nodes)

	// Create a job with a distinct_hosts constraint and two task groups.
	tg1 := &structs.TaskGroup{Name: "bar"}
	tg2 := &structs.TaskGroup{Name: "baz"}

	job := &structs.Job{
		ID:          "foo",
		Constraints: []*structs.Constraint{{Operand: structs.ConstraintDistinctHosts}},
		TaskGroups:  []*structs.TaskGroup{tg1, tg2},
	}

	// Add allocs placing tg1 on node1 and tg2 on node2. This should make the
	// job unsatisfiable on all nodes but node3
	plan := ctx.Plan()
	plan.NodeAllocation[nodes[0].ID] = []*structs.Allocation{
		&structs.Allocation{
			TaskGroup: tg1.Name,
			JobID:     job.ID,
			Job:       job,
			ID:        structs.GenerateUUID(),
		},

		// Should be ignored as it is a different job.
		&structs.Allocation{
			TaskGroup: tg2.Name,
			JobID:     "ignore 2",
			Job:       job,
			ID:        structs.GenerateUUID(),
		},
	}
	plan.NodeAllocation[nodes[1].ID] = []*structs.Allocation{
		&structs.Allocation{
			TaskGroup: tg2.Name,
			JobID:     job.ID,
			Job:       job,
			ID:        structs.GenerateUUID(),
		},

		// Should be ignored as it is a different job.
		&structs.Allocation{
			TaskGroup: tg1.Name,
			JobID:     "ignore 2",
			Job:       job,
			ID:        structs.GenerateUUID(),
		},
	}

	proposed := NewDistinctHostsIterator(ctx, static)
	proposed.SetTaskGroup(tg1)
	proposed.SetJob(job)

	out := collectFeasible(proposed)
	if len(out) != 1 {
		t.Fatalf("Bad: %#v", out)
	}

	if out[0].ID != nodes[2].ID {
		t.Fatalf("wrong node picked")
	}
}

func TestDistinctHostsIterator_JobDistinctHosts_InfeasibleCount(t *testing.T) {
	_, ctx := testContext(t)
	nodes := []*structs.Node{
		mock.Node(),
		mock.Node(),
	}
	static := NewStaticIterator(ctx, nodes)

	// Create a job with a distinct_hosts constraint and three task groups.
	tg1 := &structs.TaskGroup{Name: "bar"}
	tg2 := &structs.TaskGroup{Name: "baz"}
	tg3 := &structs.TaskGroup{Name: "bam"}

	job := &structs.Job{
		ID:          "foo",
		Constraints: []*structs.Constraint{{Operand: structs.ConstraintDistinctHosts}},
		TaskGroups:  []*structs.TaskGroup{tg1, tg2, tg3},
	}

	// Add allocs placing tg1 on node1 and tg2 on node2. This should make the
	// job unsatisfiable for tg3
	plan := ctx.Plan()
	plan.NodeAllocation[nodes[0].ID] = []*structs.Allocation{
		&structs.Allocation{
			TaskGroup: tg1.Name,
			JobID:     job.ID,
			ID:        structs.GenerateUUID(),
		},
	}
	plan.NodeAllocation[nodes[1].ID] = []*structs.Allocation{
		&structs.Allocation{
			TaskGroup: tg2.Name,
			JobID:     job.ID,
			ID:        structs.GenerateUUID(),
		},
	}

	proposed := NewDistinctHostsIterator(ctx, static)
	proposed.SetTaskGroup(tg3)
	proposed.SetJob(job)

	// It should not be able to place 3 tasks with only two nodes.
	out := collectFeasible(proposed)
	if len(out) != 0 {
		t.Fatalf("Bad: %#v", out)
	}
}

func TestDistinctHostsIterator_TaskGroupDistinctHosts(t *testing.T) {
	_, ctx := testContext(t)
	nodes := []*structs.Node{
		mock.Node(),
		mock.Node(),
	}
	static := NewStaticIterator(ctx, nodes)

	// Create a task group with a distinct_hosts constraint.
	tg1 := &structs.TaskGroup{
		Name: "example",
		Constraints: []*structs.Constraint{
			{Operand: structs.ConstraintDistinctHosts},
		},
	}
	tg2 := &structs.TaskGroup{Name: "baz"}

	// Add a planned alloc to node1.
	plan := ctx.Plan()
	plan.NodeAllocation[nodes[0].ID] = []*structs.Allocation{
		&structs.Allocation{
			TaskGroup: tg1.Name,
			JobID:     "foo",
		},
	}

	// Add a planned alloc to node2 with the same task group name but a
	// different job.
	plan.NodeAllocation[nodes[1].ID] = []*structs.Allocation{
		&structs.Allocation{
			TaskGroup: tg1.Name,
			JobID:     "bar",
		},
	}

	proposed := NewDistinctHostsIterator(ctx, static)
	proposed.SetTaskGroup(tg1)
	proposed.SetJob(&structs.Job{ID: "foo"})

	out := collectFeasible(proposed)
	if len(out) != 1 {
		t.Fatalf("Bad: %#v", out)
	}

	// Expect it to skip the first node as there is a previous alloc on it for
	// the same task group.
	if out[0] != nodes[1] {
		t.Fatalf("Bad: %v", out)
	}

	// Since the other task group doesn't have the constraint, both nodes should
	// be feasible.
	proposed.Reset()
	proposed.SetTaskGroup(tg2)
	out = collectFeasible(proposed)
	if len(out) != 2 {
		t.Fatalf("Bad: %#v", out)
	}
}

// This test puts creates allocations across task groups that use a property
// value to detect if the constraint at the job level properly considers all
// task groups.
func TestDistinctPropertyIterator_JobDistinctProperty(t *testing.T) {
	state, ctx := testContext(t)
	nodes := []*structs.Node{
		mock.Node(),
		mock.Node(),
		mock.Node(),
		mock.Node(),
		mock.Node(),
	}

	for i, n := range nodes {
		n.Meta["rack"] = fmt.Sprintf("%d", i)

		// Add to state store
		if err := state.UpsertNode(uint64(100+i), n); err != nil {
			t.Fatalf("failed to upsert node: %v", err)
		}
	}

	static := NewStaticIterator(ctx, nodes)

	// Create a job with a distinct_property constraint and a task groups.
	tg1 := &structs.TaskGroup{Name: "bar"}
	tg2 := &structs.TaskGroup{Name: "baz"}

	job := &structs.Job{
		ID: "foo",
		Constraints: []*structs.Constraint{
			{
				Operand: structs.ConstraintDistinctProperty,
				LTarget: "${meta.rack}",
			},
		},
		TaskGroups: []*structs.TaskGroup{tg1, tg2},
	}

	// Add allocs placing tg1 on node1 and 2 and tg2 on node3 and 4. This should make the
	// job unsatisfiable on all nodes but node5. Also mix the allocations
	// existing in the plan and the state store.
	plan := ctx.Plan()
	alloc1ID := structs.GenerateUUID()
	plan.NodeAllocation[nodes[0].ID] = []*structs.Allocation{
		&structs.Allocation{
			TaskGroup: tg1.Name,
			JobID:     job.ID,
			Job:       job,
			ID:        alloc1ID,
			NodeID:    nodes[0].ID,
		},

		// Should be ignored as it is a different job.
		&structs.Allocation{
			TaskGroup: tg2.Name,
			JobID:     "ignore 2",
			Job:       job,
			ID:        structs.GenerateUUID(),
			NodeID:    nodes[0].ID,
		},
	}
	plan.NodeAllocation[nodes[2].ID] = []*structs.Allocation{
		&structs.Allocation{
			TaskGroup: tg2.Name,
			JobID:     job.ID,
			Job:       job,
			ID:        structs.GenerateUUID(),
			NodeID:    nodes[2].ID,
		},

		// Should be ignored as it is a different job.
		&structs.Allocation{
			TaskGroup: tg1.Name,
			JobID:     "ignore 2",
			Job:       job,
			ID:        structs.GenerateUUID(),
			NodeID:    nodes[2].ID,
		},
	}

	// Put an allocation on Node 5 but make it stopped in the plan
	stoppingAllocID := structs.GenerateUUID()
	plan.NodeUpdate[nodes[4].ID] = []*structs.Allocation{
		&structs.Allocation{
			TaskGroup: tg2.Name,
			JobID:     job.ID,
			Job:       job,
			ID:        stoppingAllocID,
			NodeID:    nodes[4].ID,
		},
	}

	upserting := []*structs.Allocation{
		// Have one of the allocations exist in both the plan and the state
		// store. This resembles an allocation update
		&structs.Allocation{
			TaskGroup: tg1.Name,
			JobID:     job.ID,
			Job:       job,
			ID:        alloc1ID,
			EvalID:    structs.GenerateUUID(),
			NodeID:    nodes[0].ID,
		},

		&structs.Allocation{
			TaskGroup: tg1.Name,
			JobID:     job.ID,
			Job:       job,
			ID:        structs.GenerateUUID(),
			EvalID:    structs.GenerateUUID(),
			NodeID:    nodes[1].ID,
		},

		// Should be ignored as it is a different job.
		&structs.Allocation{
			TaskGroup: tg2.Name,
			JobID:     "ignore 2",
			Job:       job,
			ID:        structs.GenerateUUID(),
			EvalID:    structs.GenerateUUID(),
			NodeID:    nodes[1].ID,
		},
		&structs.Allocation{
			TaskGroup: tg2.Name,
			JobID:     job.ID,
			Job:       job,
			ID:        structs.GenerateUUID(),
			EvalID:    structs.GenerateUUID(),
			NodeID:    nodes[3].ID,
		},

		// Should be ignored as it is a different job.
		&structs.Allocation{
			TaskGroup: tg1.Name,
			JobID:     "ignore 2",
			Job:       job,
			ID:        structs.GenerateUUID(),
			EvalID:    structs.GenerateUUID(),
			NodeID:    nodes[3].ID,
		},
		&structs.Allocation{
			TaskGroup: tg2.Name,
			JobID:     job.ID,
			Job:       job,
			ID:        stoppingAllocID,
			EvalID:    structs.GenerateUUID(),
			NodeID:    nodes[4].ID,
		},
	}
	if err := state.UpsertAllocs(1000, upserting); err != nil {
		t.Fatalf("failed to UpsertAllocs: %v", err)
	}

	proposed := NewDistinctPropertyIterator(ctx, static)
	proposed.SetJob(job)
	proposed.SetTaskGroup(tg2)
	proposed.Reset()

	out := collectFeasible(proposed)
	if len(out) != 1 {
		t.Fatalf("Bad: %#v", out)
	}
	if out[0].ID != nodes[4].ID {
		t.Fatalf("wrong node picked")
	}
}

// This test creates allocations across task groups that use a property value to
// detect if the constraint at the job level properly considers all task groups
// when the constraint allows a count greater than one
func TestDistinctPropertyIterator_JobDistinctProperty_Count(t *testing.T) {
	state, ctx := testContext(t)
	nodes := []*structs.Node{
		mock.Node(),
		mock.Node(),
		mock.Node(),
	}

	for i, n := range nodes {
		n.Meta["rack"] = fmt.Sprintf("%d", i)

		// Add to state store
		if err := state.UpsertNode(uint64(100+i), n); err != nil {
			t.Fatalf("failed to upsert node: %v", err)
		}
	}

	static := NewStaticIterator(ctx, nodes)

	// Create a job with a distinct_property constraint and a task groups.
	tg1 := &structs.TaskGroup{Name: "bar"}
	tg2 := &structs.TaskGroup{Name: "baz"}

	job := &structs.Job{
		ID: "foo",
		Constraints: []*structs.Constraint{
			{
				Operand: structs.ConstraintDistinctProperty,
				LTarget: "${meta.rack}",
				RTarget: "2",
			},
		},
		TaskGroups: []*structs.TaskGroup{tg1, tg2},
	}

	// Add allocs placing two allocations on both node 1 and 2 and only one on
	// node 3. This should make the job unsatisfiable on all nodes but node5.
	// Also mix the allocations existing in the plan and the state store.
	plan := ctx.Plan()
	alloc1ID := structs.GenerateUUID()
	plan.NodeAllocation[nodes[0].ID] = []*structs.Allocation{
		&structs.Allocation{
			TaskGroup: tg1.Name,
			JobID:     job.ID,
			Job:       job,
			ID:        alloc1ID,
			NodeID:    nodes[0].ID,
		},

		&structs.Allocation{
			TaskGroup: tg2.Name,
			JobID:     job.ID,
			Job:       job,
			ID:        alloc1ID,
			NodeID:    nodes[0].ID,
		},

		// Should be ignored as it is a different job.
		&structs.Allocation{
			TaskGroup: tg2.Name,
			JobID:     "ignore 2",
			Job:       job,
			ID:        structs.GenerateUUID(),
			NodeID:    nodes[0].ID,
		},
	}
	plan.NodeAllocation[nodes[1].ID] = []*structs.Allocation{
		&structs.Allocation{
			TaskGroup: tg1.Name,
			JobID:     job.ID,
			Job:       job,
			ID:        structs.GenerateUUID(),
			NodeID:    nodes[1].ID,
		},

		&structs.Allocation{
			TaskGroup: tg2.Name,
			JobID:     job.ID,
			Job:       job,
			ID:        structs.GenerateUUID(),
			NodeID:    nodes[1].ID,
		},

		// Should be ignored as it is a different job.
		&structs.Allocation{
			TaskGroup: tg1.Name,
			JobID:     "ignore 2",
			Job:       job,
			ID:        structs.GenerateUUID(),
			NodeID:    nodes[1].ID,
		},
	}
	plan.NodeAllocation[nodes[2].ID] = []*structs.Allocation{
		&structs.Allocation{
			TaskGroup: tg1.Name,
			JobID:     job.ID,
			Job:       job,
			ID:        structs.GenerateUUID(),
			NodeID:    nodes[2].ID,
		},

		// Should be ignored as it is a different job.
		&structs.Allocation{
			TaskGroup: tg1.Name,
			JobID:     "ignore 2",
			Job:       job,
			ID:        structs.GenerateUUID(),
			NodeID:    nodes[2].ID,
		},
	}

	// Put an allocation on Node 3 but make it stopped in the plan
	stoppingAllocID := structs.GenerateUUID()
	plan.NodeUpdate[nodes[2].ID] = []*structs.Allocation{
		&structs.Allocation{
			TaskGroup: tg2.Name,
			JobID:     job.ID,
			Job:       job,
			ID:        stoppingAllocID,
			NodeID:    nodes[2].ID,
		},
	}

	upserting := []*structs.Allocation{
		// Have one of the allocations exist in both the plan and the state
		// store. This resembles an allocation update
		&structs.Allocation{
			TaskGroup: tg1.Name,
			JobID:     job.ID,
			Job:       job,
			ID:        alloc1ID,
			EvalID:    structs.GenerateUUID(),
			NodeID:    nodes[0].ID,
		},

		&structs.Allocation{
			TaskGroup: tg1.Name,
			JobID:     job.ID,
			Job:       job,
			ID:        structs.GenerateUUID(),
			EvalID:    structs.GenerateUUID(),
			NodeID:    nodes[1].ID,
		},

		&structs.Allocation{
			TaskGroup: tg2.Name,
			JobID:     job.ID,
			Job:       job,
			ID:        structs.GenerateUUID(),
			EvalID:    structs.GenerateUUID(),
			NodeID:    nodes[0].ID,
		},

		// Should be ignored as it is a different job.
		&structs.Allocation{
			TaskGroup: tg1.Name,
			JobID:     "ignore 2",
			Job:       job,
			ID:        structs.GenerateUUID(),
			EvalID:    structs.GenerateUUID(),
			NodeID:    nodes[1].ID,
		},
		&structs.Allocation{
			TaskGroup: tg2.Name,
			JobID:     "ignore 2",
			Job:       job,
			ID:        structs.GenerateUUID(),
			EvalID:    structs.GenerateUUID(),
			NodeID:    nodes[1].ID,
		},
	}
	if err := state.UpsertAllocs(1000, upserting); err != nil {
		t.Fatalf("failed to UpsertAllocs: %v", err)
	}

	proposed := NewDistinctPropertyIterator(ctx, static)
	proposed.SetJob(job)
	proposed.SetTaskGroup(tg2)
	proposed.Reset()

	out := collectFeasible(proposed)
	if len(out) != 1 {
		t.Fatalf("Bad: %#v", out)
	}
	if out[0].ID != nodes[2].ID {
		t.Fatalf("wrong node picked")
	}
}

// This test checks that if a node has an allocation on it that gets stopped,
// there is a plan to re-use that for a new allocation, that the next select
// won't select that node.
func TestDistinctPropertyIterator_JobDistinctProperty_RemoveAndReplace(t *testing.T) {
	state, ctx := testContext(t)
	nodes := []*structs.Node{
		mock.Node(),
	}

	nodes[0].Meta["rack"] = "1"

	// Add to state store
	if err := state.UpsertNode(uint64(100), nodes[0]); err != nil {
		t.Fatalf("failed to upsert node: %v", err)
	}

	static := NewStaticIterator(ctx, nodes)

	// Create a job with a distinct_property constraint and a task groups.
	tg1 := &structs.TaskGroup{Name: "bar"}
	job := &structs.Job{
		ID: "foo",
		Constraints: []*structs.Constraint{
			{
				Operand: structs.ConstraintDistinctProperty,
				LTarget: "${meta.rack}",
			},
		},
		TaskGroups: []*structs.TaskGroup{tg1},
	}

	plan := ctx.Plan()
	plan.NodeAllocation[nodes[0].ID] = []*structs.Allocation{
		&structs.Allocation{
			TaskGroup: tg1.Name,
			JobID:     job.ID,
			Job:       job,
			ID:        structs.GenerateUUID(),
			NodeID:    nodes[0].ID,
		},
	}

	stoppingAllocID := structs.GenerateUUID()
	plan.NodeUpdate[nodes[0].ID] = []*structs.Allocation{
		&structs.Allocation{
			TaskGroup: tg1.Name,
			JobID:     job.ID,
			Job:       job,
			ID:        stoppingAllocID,
			NodeID:    nodes[0].ID,
		},
	}

	upserting := []*structs.Allocation{
		&structs.Allocation{
			TaskGroup: tg1.Name,
			JobID:     job.ID,
			Job:       job,
			ID:        stoppingAllocID,
			EvalID:    structs.GenerateUUID(),
			NodeID:    nodes[0].ID,
		},
	}
	if err := state.UpsertAllocs(1000, upserting); err != nil {
		t.Fatalf("failed to UpsertAllocs: %v", err)
	}

	proposed := NewDistinctPropertyIterator(ctx, static)
	proposed.SetJob(job)
	proposed.SetTaskGroup(tg1)
	proposed.Reset()

	out := collectFeasible(proposed)
	if len(out) != 0 {
		t.Fatalf("Bad: %#v", out)
	}
}

// This test creates previous allocations selecting certain property values to
// test if it detects infeasibility of property values correctly and picks the
// only feasible one
func TestDistinctPropertyIterator_JobDistinctProperty_Infeasible(t *testing.T) {
	state, ctx := testContext(t)
	nodes := []*structs.Node{
		mock.Node(),
		mock.Node(),
	}

	for i, n := range nodes {
		n.Meta["rack"] = fmt.Sprintf("%d", i)

		// Add to state store
		if err := state.UpsertNode(uint64(100+i), n); err != nil {
			t.Fatalf("failed to upsert node: %v", err)
		}
	}

	static := NewStaticIterator(ctx, nodes)

	// Create a job with a distinct_property constraint and a task groups.
	tg1 := &structs.TaskGroup{Name: "bar"}
	tg2 := &structs.TaskGroup{Name: "baz"}
	tg3 := &structs.TaskGroup{Name: "bam"}

	job := &structs.Job{
		ID: "foo",
		Constraints: []*structs.Constraint{
			{
				Operand: structs.ConstraintDistinctProperty,
				LTarget: "${meta.rack}",
			},
		},
		TaskGroups: []*structs.TaskGroup{tg1, tg2, tg3},
	}

	// Add allocs placing tg1 on node1 and tg2 on node2. This should make the
	// job unsatisfiable for tg3.
	plan := ctx.Plan()
	plan.NodeAllocation[nodes[0].ID] = []*structs.Allocation{
		&structs.Allocation{
			TaskGroup: tg1.Name,
			JobID:     job.ID,
			Job:       job,
			ID:        structs.GenerateUUID(),
			NodeID:    nodes[0].ID,
		},
	}
	upserting := []*structs.Allocation{
		&structs.Allocation{
			TaskGroup: tg2.Name,
			JobID:     job.ID,
			Job:       job,
			ID:        structs.GenerateUUID(),
			EvalID:    structs.GenerateUUID(),
			NodeID:    nodes[1].ID,
		},
	}
	if err := state.UpsertAllocs(1000, upserting); err != nil {
		t.Fatalf("failed to UpsertAllocs: %v", err)
	}

	proposed := NewDistinctPropertyIterator(ctx, static)
	proposed.SetJob(job)
	proposed.SetTaskGroup(tg3)
	proposed.Reset()

	out := collectFeasible(proposed)
	if len(out) != 0 {
		t.Fatalf("Bad: %#v", out)
	}
}

// This test creates previous allocations selecting certain property values to
// test if it detects infeasibility of property values correctly and picks the
// only feasible one
func TestDistinctPropertyIterator_JobDistinctProperty_Infeasible_Count(t *testing.T) {
	state, ctx := testContext(t)
	nodes := []*structs.Node{
		mock.Node(),
		mock.Node(),
	}

	for i, n := range nodes {
		n.Meta["rack"] = fmt.Sprintf("%d", i)

		// Add to state store
		if err := state.UpsertNode(uint64(100+i), n); err != nil {
			t.Fatalf("failed to upsert node: %v", err)
		}
	}

	static := NewStaticIterator(ctx, nodes)

	// Create a job with a distinct_property constraint and a task groups.
	tg1 := &structs.TaskGroup{Name: "bar"}
	tg2 := &structs.TaskGroup{Name: "baz"}
	tg3 := &structs.TaskGroup{Name: "bam"}

	job := &structs.Job{
		ID: "foo",
		Constraints: []*structs.Constraint{
			{
				Operand: structs.ConstraintDistinctProperty,
				LTarget: "${meta.rack}",
				RTarget: "2",
			},
		},
		TaskGroups: []*structs.TaskGroup{tg1, tg2, tg3},
	}

	// Add allocs placing two tg1's on node1 and two tg2's on node2. This should
	// make the job unsatisfiable for tg3.
	plan := ctx.Plan()
	plan.NodeAllocation[nodes[0].ID] = []*structs.Allocation{
		&structs.Allocation{
			TaskGroup: tg1.Name,
			JobID:     job.ID,
			Job:       job,
			ID:        structs.GenerateUUID(),
			NodeID:    nodes[0].ID,
		},
		&structs.Allocation{
			TaskGroup: tg2.Name,
			JobID:     job.ID,
			Job:       job,
			ID:        structs.GenerateUUID(),
			NodeID:    nodes[0].ID,
		},
	}
	upserting := []*structs.Allocation{
		&structs.Allocation{
			TaskGroup: tg1.Name,
			JobID:     job.ID,
			Job:       job,
			ID:        structs.GenerateUUID(),
			EvalID:    structs.GenerateUUID(),
			NodeID:    nodes[1].ID,
		},
		&structs.Allocation{
			TaskGroup: tg2.Name,
			JobID:     job.ID,
			Job:       job,
			ID:        structs.GenerateUUID(),
			EvalID:    structs.GenerateUUID(),
			NodeID:    nodes[1].ID,
		},
	}
	if err := state.UpsertAllocs(1000, upserting); err != nil {
		t.Fatalf("failed to UpsertAllocs: %v", err)
	}

	proposed := NewDistinctPropertyIterator(ctx, static)
	proposed.SetJob(job)
	proposed.SetTaskGroup(tg3)
	proposed.Reset()

	out := collectFeasible(proposed)
	if len(out) != 0 {
		t.Fatalf("Bad: %#v", out)
	}
}

// This test creates previous allocations selecting certain property values to
// test if it detects infeasibility of property values correctly and picks the
// only feasible one when the constraint is at the task group.
func TestDistinctPropertyIterator_TaskGroupDistinctProperty(t *testing.T) {
	state, ctx := testContext(t)
	nodes := []*structs.Node{
		mock.Node(),
		mock.Node(),
		mock.Node(),
	}

	for i, n := range nodes {
		n.Meta["rack"] = fmt.Sprintf("%d", i)

		// Add to state store
		if err := state.UpsertNode(uint64(100+i), n); err != nil {
			t.Fatalf("failed to upsert node: %v", err)
		}
	}

	static := NewStaticIterator(ctx, nodes)

	// Create a job with a task group with the distinct_property constraint
	tg1 := &structs.TaskGroup{
		Name: "example",
		Constraints: []*structs.Constraint{
			{
				Operand: structs.ConstraintDistinctProperty,
				LTarget: "${meta.rack}",
			},
		},
	}
	tg2 := &structs.TaskGroup{Name: "baz"}

	job := &structs.Job{
		ID:         "foo",
		TaskGroups: []*structs.TaskGroup{tg1, tg2},
	}

	// Add allocs placing tg1 on node1 and 2. This should make the
	// job unsatisfiable on all nodes but node3. Also mix the allocations
	// existing in the plan and the state store.
	plan := ctx.Plan()
	plan.NodeAllocation[nodes[0].ID] = []*structs.Allocation{
		&structs.Allocation{
			TaskGroup: tg1.Name,
			JobID:     job.ID,
			Job:       job,
			ID:        structs.GenerateUUID(),
			NodeID:    nodes[0].ID,
		},
	}

	// Put an allocation on Node 3 but make it stopped in the plan
	stoppingAllocID := structs.GenerateUUID()
	plan.NodeUpdate[nodes[2].ID] = []*structs.Allocation{
		&structs.Allocation{
			TaskGroup: tg1.Name,
			JobID:     job.ID,
			Job:       job,
			ID:        stoppingAllocID,
			NodeID:    nodes[2].ID,
		},
	}

	upserting := []*structs.Allocation{
		&structs.Allocation{
			TaskGroup: tg1.Name,
			JobID:     job.ID,
			Job:       job,
			ID:        structs.GenerateUUID(),
			EvalID:    structs.GenerateUUID(),
			NodeID:    nodes[1].ID,
		},

		// Should be ignored as it is a different job.
		&structs.Allocation{
			TaskGroup: tg1.Name,
			JobID:     "ignore 2",
			Job:       job,
			ID:        structs.GenerateUUID(),
			EvalID:    structs.GenerateUUID(),
			NodeID:    nodes[2].ID,
		},

		&structs.Allocation{
			TaskGroup: tg1.Name,
			JobID:     job.ID,
			Job:       job,
			ID:        stoppingAllocID,
			EvalID:    structs.GenerateUUID(),
			NodeID:    nodes[2].ID,
		},
	}
	if err := state.UpsertAllocs(1000, upserting); err != nil {
		t.Fatalf("failed to UpsertAllocs: %v", err)
	}

	proposed := NewDistinctPropertyIterator(ctx, static)
	proposed.SetJob(job)
	proposed.SetTaskGroup(tg1)
	proposed.Reset()

	out := collectFeasible(proposed)
	if len(out) != 1 {
		t.Fatalf("Bad: %#v", out)
	}
	if out[0].ID != nodes[2].ID {
		t.Fatalf("wrong node picked")
	}

	// Since the other task group doesn't have the constraint, both nodes should
	// be feasible.
	proposed.SetTaskGroup(tg2)
	proposed.Reset()

	out = collectFeasible(proposed)
	if len(out) != 3 {
		t.Fatalf("Bad: %#v", out)
	}
}

func collectFeasible(iter FeasibleIterator) (out []*structs.Node) {
	for {
		next := iter.Next()
		if next == nil {
			break
		}
		out = append(out, next)
	}
	return
}

// mockFeasibilityChecker is a FeasibilityChecker that returns predetermined
// feasibility values.
type mockFeasibilityChecker struct {
	retVals []bool
	i       int
}

func newMockFeasiblityChecker(values ...bool) *mockFeasibilityChecker {
	return &mockFeasibilityChecker{retVals: values}
}

func (c *mockFeasibilityChecker) Feasible(*structs.Node) bool {
	if c.i >= len(c.retVals) {
		c.i++
		return false
	}

	f := c.retVals[c.i]
	c.i++
	return f
}

// calls returns how many times the checker was called.
func (c *mockFeasibilityChecker) calls() int { return c.i }

func TestFeasibilityWrapper_JobIneligible(t *testing.T) {
	_, ctx := testContext(t)
	nodes := []*structs.Node{mock.Node()}
	static := NewStaticIterator(ctx, nodes)
	mocked := newMockFeasiblityChecker(false)
	wrapper := NewFeasibilityWrapper(ctx, static, []FeasibilityChecker{mocked}, nil)

	// Set the job to ineligible
	ctx.Eligibility().SetJobEligibility(false, nodes[0].ComputedClass)

	// Run the wrapper.
	out := collectFeasible(wrapper)

	if out != nil || mocked.calls() != 0 {
		t.Fatalf("bad: %#v %d", out, mocked.calls())
	}
}

func TestFeasibilityWrapper_JobEscapes(t *testing.T) {
	_, ctx := testContext(t)
	nodes := []*structs.Node{mock.Node()}
	static := NewStaticIterator(ctx, nodes)
	mocked := newMockFeasiblityChecker(false)
	wrapper := NewFeasibilityWrapper(ctx, static, []FeasibilityChecker{mocked}, nil)

	// Set the job to escaped
	cc := nodes[0].ComputedClass
	ctx.Eligibility().job[cc] = EvalComputedClassEscaped

	// Run the wrapper.
	out := collectFeasible(wrapper)

	if out != nil || mocked.calls() != 1 {
		t.Fatalf("bad: %#v", out)
	}

	// Ensure that the job status didn't change from escaped even though the
	// option failed.
	if status := ctx.Eligibility().JobStatus(cc); status != EvalComputedClassEscaped {
		t.Fatalf("job status is %v; want %v", status, EvalComputedClassEscaped)
	}
}

func TestFeasibilityWrapper_JobAndTg_Eligible(t *testing.T) {
	_, ctx := testContext(t)
	nodes := []*structs.Node{mock.Node()}
	static := NewStaticIterator(ctx, nodes)
	jobMock := newMockFeasiblityChecker(true)
	tgMock := newMockFeasiblityChecker(false)
	wrapper := NewFeasibilityWrapper(ctx, static, []FeasibilityChecker{jobMock}, []FeasibilityChecker{tgMock})

	// Set the job to escaped
	cc := nodes[0].ComputedClass
	ctx.Eligibility().job[cc] = EvalComputedClassEligible
	ctx.Eligibility().SetTaskGroupEligibility(true, "foo", cc)
	wrapper.SetTaskGroup("foo")

	// Run the wrapper.
	out := collectFeasible(wrapper)

	if out == nil || tgMock.calls() != 0 {
		t.Fatalf("bad: %#v %v", out, tgMock.calls())
	}
}

func TestFeasibilityWrapper_JobEligible_TgIneligible(t *testing.T) {
	_, ctx := testContext(t)
	nodes := []*structs.Node{mock.Node()}
	static := NewStaticIterator(ctx, nodes)
	jobMock := newMockFeasiblityChecker(true)
	tgMock := newMockFeasiblityChecker(false)
	wrapper := NewFeasibilityWrapper(ctx, static, []FeasibilityChecker{jobMock}, []FeasibilityChecker{tgMock})

	// Set the job to escaped
	cc := nodes[0].ComputedClass
	ctx.Eligibility().job[cc] = EvalComputedClassEligible
	ctx.Eligibility().SetTaskGroupEligibility(false, "foo", cc)
	wrapper.SetTaskGroup("foo")

	// Run the wrapper.
	out := collectFeasible(wrapper)

	if out != nil || tgMock.calls() != 0 {
		t.Fatalf("bad: %#v %v", out, tgMock.calls())
	}
}

func TestFeasibilityWrapper_JobEligible_TgEscaped(t *testing.T) {
	_, ctx := testContext(t)
	nodes := []*structs.Node{mock.Node()}
	static := NewStaticIterator(ctx, nodes)
	jobMock := newMockFeasiblityChecker(true)
	tgMock := newMockFeasiblityChecker(true)
	wrapper := NewFeasibilityWrapper(ctx, static, []FeasibilityChecker{jobMock}, []FeasibilityChecker{tgMock})

	// Set the job to escaped
	cc := nodes[0].ComputedClass
	ctx.Eligibility().job[cc] = EvalComputedClassEligible
	ctx.Eligibility().taskGroups["foo"] =
		map[string]ComputedClassFeasibility{cc: EvalComputedClassEscaped}
	wrapper.SetTaskGroup("foo")

	// Run the wrapper.
	out := collectFeasible(wrapper)

	if out == nil || tgMock.calls() != 1 {
		t.Fatalf("bad: %#v %v", out, tgMock.calls())
	}

	if e, ok := ctx.Eligibility().taskGroups["foo"][cc]; !ok || e != EvalComputedClassEscaped {
		t.Fatalf("bad: %v %v", e, ok)
	}
}