context_test.go - platform/build/blueprint - Gitiles

 // Copyright 2014 Google Inc. 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 blueprint

 import (
 	"bytes"
 	"errors"
 	"fmt"
 	"reflect"
 	"strings"
 	"sync"
 	"testing"
 	"time"

 	"github.com/google/blueprint/parser"
 )

 type Walker interface {
 	Walk() bool
 }

 type fooModule struct {
 	SimpleName
 	properties struct {
 		Deps []string
 		Foo  string
 	}
 }

 func newFooModule() (Module, []interface{}) {
 	m := &fooModule{}
 	return m, []interface{}{&m.properties, &m.SimpleName.Properties}
 }

 func (f *fooModule) GenerateBuildActions(ModuleContext) {
 }

 func (f *fooModule) DynamicDependencies(ctx DynamicDependerModuleContext) []string {
 	return f.properties.Deps
 }

 func (f *fooModule) Foo() string {
 	return f.properties.Foo
 }

 func (f *fooModule) Walk() bool {
 	return true
 }

 type barModule struct {
 	SimpleName
 	properties struct {
 		Deps []string
 		Bar  bool
 	}
 }

 func newBarModule() (Module, []interface{}) {
 	m := &barModule{}
 	return m, []interface{}{&m.properties, &m.SimpleName.Properties}
 }

 func (b *barModule) DynamicDependencies(ctx DynamicDependerModuleContext) []string {
 	return b.properties.Deps
 }

 func (b *barModule) GenerateBuildActions(ModuleContext) {
 }

 func (b *barModule) Bar() bool {
 	return b.properties.Bar
 }

 func (b *barModule) Walk() bool {
 	return false
 }

 func TestContextParse(t *testing.T) {
 	ctx := NewContext()
 	ctx.RegisterModuleType("foo_module", newFooModule)
 	ctx.RegisterModuleType("bar_module", newBarModule)

 	r := bytes.NewBufferString(`
 		foo_module {
 	        name: "MyFooModule",
 			deps: ["MyBarModule"],
 		}

 		bar_module {
 	        name: "MyBarModule",
 		}
 	`)

 	_, _, errs := ctx.parseOne(".", "Blueprint", r, parser.NewScope(nil), nil)
 	if len(errs) > 0 {
 		t.Errorf("unexpected parse errors:")
 		for _, err := range errs {
 			t.Errorf("  %s", err)
 		}
 		t.FailNow()
 	}

 	_, errs = ctx.ResolveDependencies(nil)
 	if len(errs) > 0 {
 		t.Errorf("unexpected dep errors:")
 		for _, err := range errs {
 			t.Errorf("  %s", err)
 		}
 		t.FailNow()
 	}
 }

 // |===B---D       - represents a non-walkable edge
 // A               = represents a walkable edge
 // |===C===E---G
 //     |       |   A should not be visited because it's the root node.
 //     |===F===|   B, D and E should not be walked.
 func TestWalkDeps(t *testing.T) {
 	ctx := NewContext()
 	ctx.MockFileSystem(map[string][]byte{
 		"Blueprints": []byte(`
 			foo_module {
 			    name: "A",
 			    deps: ["B", "C"],
 			}

 			bar_module {
 			    name: "B",
 			    deps: ["D"],
 			}

 			foo_module {
 			    name: "C",
 			    deps: ["E", "F"],
 			}

 			foo_module {
 			    name: "D",
 			}

 			bar_module {
 			    name: "E",
 			    deps: ["G"],
 			}

 			foo_module {
 			    name: "F",
 			    deps: ["G"],
 			}

 			foo_module {
 			    name: "G",
 			}
 		`),
 	})

 	ctx.RegisterModuleType("foo_module", newFooModule)
 	ctx.RegisterModuleType("bar_module", newBarModule)
 	_, errs := ctx.ParseBlueprintsFiles("Blueprints")
 	if len(errs) > 0 {
 		t.Errorf("unexpected parse errors:")
 		for _, err := range errs {
 			t.Errorf("  %s", err)
 		}
 		t.FailNow()
 	}

 	_, errs = ctx.ResolveDependencies(nil)
 	if len(errs) > 0 {
 		t.Errorf("unexpected dep errors:")
 		for _, err := range errs {
 			t.Errorf("  %s", err)
 		}
 		t.FailNow()
 	}

 	var outputDown string
 	var outputUp string
 	topModule := ctx.modulesFromName("A", nil)[0]
 	ctx.walkDeps(topModule, false,
 		func(dep depInfo, parent *moduleInfo) bool {
 			outputDown += ctx.ModuleName(dep.module.logicModule)
 			if dep.module.logicModule.(Walker).Walk() {
 				return true
 			}
 			return false
 		},
 		func(dep depInfo, parent *moduleInfo) {
 			outputUp += ctx.ModuleName(dep.module.logicModule)
 		})
 	if outputDown != "BCEFG" {
 		t.Errorf("unexpected walkDeps behaviour: %s\ndown should be: BCEFG", outputDown)
 	}
 	if outputUp != "BEGFC" {
 		t.Errorf("unexpected walkDeps behaviour: %s\nup should be: BEGFC", outputUp)
 	}
 }

 // |===B---D           - represents a non-walkable edge
 // A                   = represents a walkable edge
 // |===C===E===\       A should not be visited because it's the root node.
 //     |       |       B, D should not be walked.
 //     |===F===G===H   G should be visited multiple times
 //         \===/       H should only be visited once
 func TestWalkDepsDuplicates(t *testing.T) {
 	ctx := NewContext()
 	ctx.MockFileSystem(map[string][]byte{
 		"Blueprints": []byte(`
 			foo_module {
 			    name: "A",
 			    deps: ["B", "C"],
 			}

 			bar_module {
 			    name: "B",
 			    deps: ["D"],
 			}

 			foo_module {
 			    name: "C",
 			    deps: ["E", "F"],
 			}

 			foo_module {
 			    name: "D",
 			}

 			foo_module {
 			    name: "E",
 			    deps: ["G"],
 			}

 			foo_module {
 			    name: "F",
 			    deps: ["G", "G"],
 			}

 			foo_module {
 			    name: "G",
 				deps: ["H"],
 			}

 			foo_module {
 			    name: "H",
 			}
 		`),
 	})

 	ctx.RegisterModuleType("foo_module", newFooModule)
 	ctx.RegisterModuleType("bar_module", newBarModule)
 	_, errs := ctx.ParseBlueprintsFiles("Blueprints")
 	if len(errs) > 0 {
 		t.Errorf("unexpected parse errors:")
 		for _, err := range errs {
 			t.Errorf("  %s", err)
 		}
 		t.FailNow()
 	}

 	_, errs = ctx.ResolveDependencies(nil)
 	if len(errs) > 0 {
 		t.Errorf("unexpected dep errors:")
 		for _, err := range errs {
 			t.Errorf("  %s", err)
 		}
 		t.FailNow()
 	}

 	var outputDown string
 	var outputUp string
 	topModule := ctx.modulesFromName("A", nil)[0]
 	ctx.walkDeps(topModule, true,
 		func(dep depInfo, parent *moduleInfo) bool {
 			outputDown += ctx.ModuleName(dep.module.logicModule)
 			if dep.module.logicModule.(Walker).Walk() {
 				return true
 			}
 			return false
 		},
 		func(dep depInfo, parent *moduleInfo) {
 			outputUp += ctx.ModuleName(dep.module.logicModule)
 		})
 	if outputDown != "BCEGHFGG" {
 		t.Errorf("unexpected walkDeps behaviour: %s\ndown should be: BCEGHFGG", outputDown)
 	}
 	if outputUp != "BHGEGGFC" {
 		t.Errorf("unexpected walkDeps behaviour: %s\nup should be: BHGEGGFC", outputUp)
 	}
 }

 func TestCreateModule(t *testing.T) {
 	ctx := newContext()
 	ctx.MockFileSystem(map[string][]byte{
 		"Blueprints": []byte(`
 			foo_module {
 			    name: "A",
 			    deps: ["B", "C"],
 			}
 		`),
 	})

 	ctx.RegisterTopDownMutator("create", createTestMutator)
 	ctx.RegisterBottomUpMutator("deps", blueprintDepsMutator)

 	ctx.RegisterModuleType("foo_module", newFooModule)
 	ctx.RegisterModuleType("bar_module", newBarModule)
 	_, errs := ctx.ParseBlueprintsFiles("Blueprints")
 	if len(errs) > 0 {
 		t.Errorf("unexpected parse errors:")
 		for _, err := range errs {
 			t.Errorf("  %s", err)
 		}
 		t.FailNow()
 	}

 	_, errs = ctx.ResolveDependencies(nil)
 	if len(errs) > 0 {
 		t.Errorf("unexpected dep errors:")
 		for _, err := range errs {
 			t.Errorf("  %s", err)
 		}
 		t.FailNow()
 	}

 	a := ctx.modulesFromName("A", nil)[0].logicModule.(*fooModule)
 	b := ctx.modulesFromName("B", nil)[0].logicModule.(*barModule)
 	c := ctx.modulesFromName("C", nil)[0].logicModule.(*barModule)
 	d := ctx.modulesFromName("D", nil)[0].logicModule.(*fooModule)

 	checkDeps := func(m Module, expected string) {
 		var deps []string
 		ctx.VisitDirectDeps(m, func(m Module) {
 			deps = append(deps, ctx.ModuleName(m))
 		})
 		got := strings.Join(deps, ",")
 		if got != expected {
 			t.Errorf("unexpected %q dependencies, got %q expected %q",
 				ctx.ModuleName(m), got, expected)
 		}
 	}

 	checkDeps(a, "B,C")
 	checkDeps(b, "D")
 	checkDeps(c, "D")
 	checkDeps(d, "")
 }

 func createTestMutator(ctx TopDownMutatorContext) {
 	type props struct {
 		Name string
 		Deps []string
 	}

 	ctx.CreateModule(newBarModule, &props{
 		Name: "B",
 		Deps: []string{"D"},
 	})

 	ctx.CreateModule(newBarModule, &props{
 		Name: "C",
 		Deps: []string{"D"},
 	})

 	ctx.CreateModule(newFooModule, &props{
 		Name: "D",
 	})
 }

 func TestWalkFileOrder(t *testing.T) {
 	// Run the test once to see how long it normally takes
 	start := time.Now()
 	doTestWalkFileOrder(t, time.Duration(0))
 	duration := time.Since(start)

 	// Run the test again, but put enough of a sleep into each visitor to detect ordering
 	// problems if they exist
 	doTestWalkFileOrder(t, duration)
 }

 // test that WalkBlueprintsFiles calls asyncVisitor in the right order
 func doTestWalkFileOrder(t *testing.T, sleepDuration time.Duration) {
 	// setup mock context
 	ctx := newContext()
 	mockFiles := map[string][]byte{
 		"Blueprints": []byte(`
 			sample_module {
 			    name: "a",
 			}
 		`),
 		"dir1/Blueprints": []byte(`
 			sample_module {
 			    name: "b",
 			}
 		`),
 		"dir1/dir2/Blueprints": []byte(`
 			sample_module {
 			    name: "c",
 			}
 		`),
 	}
 	ctx.MockFileSystem(mockFiles)

 	// prepare to monitor the visit order
 	visitOrder := []string{}
 	visitLock := sync.Mutex{}
 	correctVisitOrder := []string{"Blueprints", "dir1/Blueprints", "dir1/dir2/Blueprints"}

 	// sleep longer when processing the earlier files
 	chooseSleepDuration := func(fileName string) (duration time.Duration) {
 		duration = time.Duration(0)
 		for i := len(correctVisitOrder) - 1; i >= 0; i-- {
 			if fileName == correctVisitOrder[i] {
 				return duration
 			}
 			duration = duration + sleepDuration
 		}
 		panic("unrecognized file name " + fileName)
 	}

 	visitor := func(file *parser.File) {
 		time.Sleep(chooseSleepDuration(file.Name))
 		visitLock.Lock()
 		defer visitLock.Unlock()
 		visitOrder = append(visitOrder, file.Name)
 	}
 	keys := []string{"Blueprints", "dir1/Blueprints", "dir1/dir2/Blueprints"}

 	// visit the blueprints files
 	ctx.WalkBlueprintsFiles(".", keys, visitor)

 	// check the order
 	if !reflect.DeepEqual(visitOrder, correctVisitOrder) {
 		t.Errorf("Incorrect visit order; expected %v, got %v", correctVisitOrder, visitOrder)
 	}
 }

 // test that WalkBlueprintsFiles reports syntax errors
 func TestWalkingWithSyntaxError(t *testing.T) {
 	// setup mock context
 	ctx := newContext()
 	mockFiles := map[string][]byte{
 		"Blueprints": []byte(`
 			sample_module {
 			    name: "a" "b",
 			}
 		`),
 		"dir1/Blueprints": []byte(`
 			sample_module {
 			    name: "b",
 		`),
 		"dir1/dir2/Blueprints": []byte(`
 			sample_module {
 			    name: "c",
 			}
 		`),
 	}
 	ctx.MockFileSystem(mockFiles)

 	keys := []string{"Blueprints", "dir1/Blueprints", "dir1/dir2/Blueprints"}

 	// visit the blueprints files
 	_, errs := ctx.WalkBlueprintsFiles(".", keys, func(file *parser.File) {})

 	expectedErrs := []error{
 		errors.New(`Blueprints:3:18: expected "}", found String`),
 		errors.New(`dir1/Blueprints:4:3: expected "}", found EOF`),
 	}
 	if fmt.Sprintf("%s", expectedErrs) != fmt.Sprintf("%s", errs) {
 		t.Errorf("Incorrect errors; expected:\n%s\ngot:\n%s", expectedErrs, errs)
 	}

 }
	// Copyright 2014 Google Inc. 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 blueprint

	import (
	"bytes"
	"errors"
	"fmt"
	"reflect"
	"strings"
	"sync"
	"testing"
	"time"

	"github.com/google/blueprint/parser"
	)

	type Walker interface {
	Walk() bool
	}

	type fooModule struct {
	SimpleName
	properties struct {
	Deps []string
	Foo string
	}
	}

	func newFooModule() (Module, []interface{}) {
	m := &fooModule{}
	return m, []interface{}{&m.properties, &m.SimpleName.Properties}
	}

	func (f *fooModule) GenerateBuildActions(ModuleContext) {
	}

	func (f *fooModule) DynamicDependencies(ctx DynamicDependerModuleContext) []string {
	return f.properties.Deps
	}

	func (f *fooModule) Foo() string {
	return f.properties.Foo
	}

	func (f *fooModule) Walk() bool {
	return true
	}

	type barModule struct {
	SimpleName
	properties struct {
	Deps []string
	Bar bool
	}
	}

	func newBarModule() (Module, []interface{}) {
	m := &barModule{}
	return m, []interface{}{&m.properties, &m.SimpleName.Properties}
	}

	func (b *barModule) DynamicDependencies(ctx DynamicDependerModuleContext) []string {
	return b.properties.Deps
	}

	func (b *barModule) GenerateBuildActions(ModuleContext) {
	}

	func (b *barModule) Bar() bool {
	return b.properties.Bar
	}

	func (b *barModule) Walk() bool {
	return false
	}

	func TestContextParse(t *testing.T) {
	ctx := NewContext()
	ctx.RegisterModuleType("foo_module", newFooModule)
	ctx.RegisterModuleType("bar_module", newBarModule)

	r := bytes.NewBufferString(`
	foo_module {
	name: "MyFooModule",
	deps: ["MyBarModule"],
	}

	bar_module {
	name: "MyBarModule",
	}
	`)

	_, _, errs := ctx.parseOne(".", "Blueprint", r, parser.NewScope(nil), nil)
	if len(errs) > 0 {
	t.Errorf("unexpected parse errors:")
	for _, err := range errs {
	t.Errorf(" %s", err)
	}
	t.FailNow()
	}

	_, errs = ctx.ResolveDependencies(nil)
	if len(errs) > 0 {
	t.Errorf("unexpected dep errors:")
	for _, err := range errs {
	t.Errorf(" %s", err)
	}
	t.FailNow()
	}
	}

	// \|===B---D - represents a non-walkable edge
	// A = represents a walkable edge
	// \|===C===E---G
	// \| \| A should not be visited because it's the root node.
	// \|===F===\| B, D and E should not be walked.
	func TestWalkDeps(t *testing.T) {
	ctx := NewContext()
	ctx.MockFileSystem(map[string][]byte{
	"Blueprints": []byte(`
	foo_module {
	name: "A",
	deps: ["B", "C"],
	}

	bar_module {
	name: "B",
	deps: ["D"],
	}

	foo_module {
	name: "C",
	deps: ["E", "F"],
	}

	foo_module {
	name: "D",
	}

	bar_module {
	name: "E",
	deps: ["G"],
	}

	foo_module {
	name: "F",
	deps: ["G"],
	}

	foo_module {
	name: "G",
	}
	`),
	})

	ctx.RegisterModuleType("foo_module", newFooModule)
	ctx.RegisterModuleType("bar_module", newBarModule)
	_, errs := ctx.ParseBlueprintsFiles("Blueprints")
	if len(errs) > 0 {
	t.Errorf("unexpected parse errors:")
	for _, err := range errs {
	t.Errorf(" %s", err)
	}
	t.FailNow()
	}

	_, errs = ctx.ResolveDependencies(nil)
	if len(errs) > 0 {
	t.Errorf("unexpected dep errors:")
	for _, err := range errs {
	t.Errorf(" %s", err)
	}
	t.FailNow()
	}

	var outputDown string
	var outputUp string
	topModule := ctx.modulesFromName("A", nil)[0]
	ctx.walkDeps(topModule, false,
	func(dep depInfo, parent *moduleInfo) bool {
	outputDown += ctx.ModuleName(dep.module.logicModule)
	if dep.module.logicModule.(Walker).Walk() {
	return true
	}
	return false
	},
	func(dep depInfo, parent *moduleInfo) {
	outputUp += ctx.ModuleName(dep.module.logicModule)
	})
	if outputDown != "BCEFG" {
	t.Errorf("unexpected walkDeps behaviour: %s\ndown should be: BCEFG", outputDown)
	}
	if outputUp != "BEGFC" {
	t.Errorf("unexpected walkDeps behaviour: %s\nup should be: BEGFC", outputUp)
	}
	}

	// \|===B---D - represents a non-walkable edge
	// A = represents a walkable edge
	// \|===C===E===\ A should not be visited because it's the root node.
	// \| \| B, D should not be walked.
	// \|===F===G===H G should be visited multiple times
	// \===/ H should only be visited once
	func TestWalkDepsDuplicates(t *testing.T) {
	ctx := NewContext()
	ctx.MockFileSystem(map[string][]byte{
	"Blueprints": []byte(`
	foo_module {
	name: "A",
	deps: ["B", "C"],
	}

	bar_module {
	name: "B",
	deps: ["D"],
	}

	foo_module {
	name: "C",
	deps: ["E", "F"],
	}

	foo_module {
	name: "D",
	}

	foo_module {
	name: "E",
	deps: ["G"],
	}

	foo_module {
	name: "F",
	deps: ["G", "G"],
	}

	foo_module {
	name: "G",
	deps: ["H"],
	}

	foo_module {
	name: "H",
	}
	`),
	})

	ctx.RegisterModuleType("foo_module", newFooModule)
	ctx.RegisterModuleType("bar_module", newBarModule)
	_, errs := ctx.ParseBlueprintsFiles("Blueprints")
	if len(errs) > 0 {
	t.Errorf("unexpected parse errors:")
	for _, err := range errs {
	t.Errorf(" %s", err)
	}
	t.FailNow()
	}

	_, errs = ctx.ResolveDependencies(nil)
	if len(errs) > 0 {
	t.Errorf("unexpected dep errors:")
	for _, err := range errs {
	t.Errorf(" %s", err)
	}
	t.FailNow()
	}

	var outputDown string
	var outputUp string
	topModule := ctx.modulesFromName("A", nil)[0]
	ctx.walkDeps(topModule, true,
	func(dep depInfo, parent *moduleInfo) bool {
	outputDown += ctx.ModuleName(dep.module.logicModule)
	if dep.module.logicModule.(Walker).Walk() {
	return true
	}
	return false
	},
	func(dep depInfo, parent *moduleInfo) {
	outputUp += ctx.ModuleName(dep.module.logicModule)
	})
	if outputDown != "BCEGHFGG" {
	t.Errorf("unexpected walkDeps behaviour: %s\ndown should be: BCEGHFGG", outputDown)
	}
	if outputUp != "BHGEGGFC" {
	t.Errorf("unexpected walkDeps behaviour: %s\nup should be: BHGEGGFC", outputUp)
	}
	}

	func TestCreateModule(t *testing.T) {
	ctx := newContext()
	ctx.MockFileSystem(map[string][]byte{
	"Blueprints": []byte(`
	foo_module {
	name: "A",
	deps: ["B", "C"],
	}
	`),
	})

	ctx.RegisterTopDownMutator("create", createTestMutator)
	ctx.RegisterBottomUpMutator("deps", blueprintDepsMutator)

	ctx.RegisterModuleType("foo_module", newFooModule)
	ctx.RegisterModuleType("bar_module", newBarModule)
	_, errs := ctx.ParseBlueprintsFiles("Blueprints")
	if len(errs) > 0 {
	t.Errorf("unexpected parse errors:")
	for _, err := range errs {
	t.Errorf(" %s", err)
	}
	t.FailNow()
	}

	_, errs = ctx.ResolveDependencies(nil)
	if len(errs) > 0 {
	t.Errorf("unexpected dep errors:")
	for _, err := range errs {
	t.Errorf(" %s", err)
	}
	t.FailNow()
	}

	a := ctx.modulesFromName("A", nil)[0].logicModule.(*fooModule)
	b := ctx.modulesFromName("B", nil)[0].logicModule.(*barModule)
	c := ctx.modulesFromName("C", nil)[0].logicModule.(*barModule)
	d := ctx.modulesFromName("D", nil)[0].logicModule.(*fooModule)

	checkDeps := func(m Module, expected string) {
	var deps []string
	ctx.VisitDirectDeps(m, func(m Module) {
	deps = append(deps, ctx.ModuleName(m))
	})
	got := strings.Join(deps, ",")
	if got != expected {
	t.Errorf("unexpected %q dependencies, got %q expected %q",
	ctx.ModuleName(m), got, expected)
	}
	}

	checkDeps(a, "B,C")
	checkDeps(b, "D")
	checkDeps(c, "D")
	checkDeps(d, "")
	}

	func createTestMutator(ctx TopDownMutatorContext) {
	type props struct {
	Name string
	Deps []string
	}

	ctx.CreateModule(newBarModule, &props{
	Name: "B",
	Deps: []string{"D"},
	})

	ctx.CreateModule(newBarModule, &props{
	Name: "C",
	Deps: []string{"D"},
	})

	ctx.CreateModule(newFooModule, &props{
	Name: "D",
	})
	}

	func TestWalkFileOrder(t *testing.T) {
	// Run the test once to see how long it normally takes
	start := time.Now()
	doTestWalkFileOrder(t, time.Duration(0))
	duration := time.Since(start)

	// Run the test again, but put enough of a sleep into each visitor to detect ordering
	// problems if they exist
	doTestWalkFileOrder(t, duration)
	}

	// test that WalkBlueprintsFiles calls asyncVisitor in the right order
	func doTestWalkFileOrder(t *testing.T, sleepDuration time.Duration) {
	// setup mock context
	ctx := newContext()
	mockFiles := map[string][]byte{
	"Blueprints": []byte(`
	sample_module {
	name: "a",
	}
	`),
	"dir1/Blueprints": []byte(`
	sample_module {
	name: "b",
	}
	`),
	"dir1/dir2/Blueprints": []byte(`
	sample_module {
	name: "c",
	}
	`),
	}
	ctx.MockFileSystem(mockFiles)

	// prepare to monitor the visit order
	visitOrder := []string{}
	visitLock := sync.Mutex{}
	correctVisitOrder := []string{"Blueprints", "dir1/Blueprints", "dir1/dir2/Blueprints"}

	// sleep longer when processing the earlier files
	chooseSleepDuration := func(fileName string) (duration time.Duration) {
	duration = time.Duration(0)
	for i := len(correctVisitOrder) - 1; i >= 0; i-- {
	if fileName == correctVisitOrder[i] {
	return duration
	}
	duration = duration + sleepDuration
	}
	panic("unrecognized file name " + fileName)
	}

	visitor := func(file *parser.File) {
	time.Sleep(chooseSleepDuration(file.Name))
	visitLock.Lock()
	defer visitLock.Unlock()
	visitOrder = append(visitOrder, file.Name)
	}
	keys := []string{"Blueprints", "dir1/Blueprints", "dir1/dir2/Blueprints"}

	// visit the blueprints files
	ctx.WalkBlueprintsFiles(".", keys, visitor)

	// check the order
	if !reflect.DeepEqual(visitOrder, correctVisitOrder) {
	t.Errorf("Incorrect visit order; expected %v, got %v", correctVisitOrder, visitOrder)
	}
	}

	// test that WalkBlueprintsFiles reports syntax errors
	func TestWalkingWithSyntaxError(t *testing.T) {
	// setup mock context
	ctx := newContext()
	mockFiles := map[string][]byte{
	"Blueprints": []byte(`
	sample_module {
	name: "a" "b",
	}
	`),
	"dir1/Blueprints": []byte(`
	sample_module {
	name: "b",
	`),
	"dir1/dir2/Blueprints": []byte(`
	sample_module {
	name: "c",
	}
	`),
	}
	ctx.MockFileSystem(mockFiles)

	keys := []string{"Blueprints", "dir1/Blueprints", "dir1/dir2/Blueprints"}

	// visit the blueprints files
	_, errs := ctx.WalkBlueprintsFiles(".", keys, func(file *parser.File) {})

	expectedErrs := []error{
	errors.New(`Blueprints:3:18: expected "}", found String`),
	errors.New(`dir1/Blueprints:4:3: expected "}", found EOF`),
	}
	if fmt.Sprintf("%s", expectedErrs) != fmt.Sprintf("%s", errs) {
	t.Errorf("Incorrect errors; expected:\n%s\ngot:\n%s", expectedErrs, errs)
	}

	}