#1: Fix race conditions errors and rewrite tests

Gopkg.lock

@@ -226,10 +226,23 @@
   revision = "25b30aa063fc18e48662b86996252eabdcf2f0c7"
   version = "v1.0.0"
 
+[[projects]]
+  digest = "1:711eebe744c0151a9d09af2315f0bb729b2ec7637ef4c410fa90a18ef74b65b6"
+  name = "github.com/stretchr/objx"
+  packages = ["."]
+  pruneopts = ""
+  revision = "477a77ecc69700c7cdeb1fa9e129548e1c1c393c"
+  version = "v0.1.1"
+
 [[projects]]
   digest = "1:381bcbeb112a51493d9d998bbba207a529c73dbb49b3fd789e48c63fac1f192c"
   name = "github.com/stretchr/testify"
-  packages = ["assert"]
+  packages = [
+    "assert",
+    "mock",
+    "require",
+    "suite",
+  ]
   pruneopts = ""
   revision = "ffdc059bfe9ce6a4e144ba849dbedead332c6053"
   version = "v1.3.0"
@@ -303,6 +316,8 @@
     "github.com/spf13/cobra",
     "github.com/spf13/viper",
     "github.com/stretchr/testify/assert",
+    "github.com/stretchr/testify/mock",
+    "github.com/stretchr/testify/suite",
     "github.com/thedevsaddam/govalidator",
     "gopkg.in/h2non/gock.v1",
   ]

api/mojang/queue/jobs_structure.go

@@ -25,24 +25,29 @@ func (s *jobsQueue) New() *jobsQueue {
 
 func (s *jobsQueue) Enqueue(t *jobItem) {
 	s.lock.Lock()
+	defer s.lock.Unlock()
+
 	s.items = append(s.items, t)
-	s.lock.Unlock()
 }
 
 func (s *jobsQueue) Dequeue(n int) []*jobItem {
 	s.lock.Lock()
+	defer s.lock.Unlock()
+
 	if n > s.Size() {
 		n = s.Size()
 	}
 
 	items := s.items[0:n]
 	s.items = s.items[n:len(s.items)]
-	s.lock.Unlock()
 
 	return items
 }
 
 func (s *jobsQueue) IsEmpty() bool {
+	s.lock.Lock()
+	defer s.lock.Unlock()
+
 	return len(s.items) == 0
 }
 

api/mojang/queue/queue.go

@@ -11,6 +11,9 @@ import (
 var usernamesToUuids = mojang.UsernamesToUuids
 var uuidToTextures = mojang.UuidToTextures
 var delay = time.Second
+var forever = func() bool {
+	return true
+}
 
 type JobsQueue struct {
 	Storage Storage
@@ -19,7 +22,7 @@ type JobsQueue struct {
 	queue       jobsQueue
 }
 
-func (ctx *JobsQueue) GetTexturesForUsername(username string) *mojang.SignedTexturesResponse {
+func (ctx *JobsQueue) GetTexturesForUsername(username string) chan *mojang.SignedTexturesResponse {
 	ctx.onFirstCall.Do(func() {
 		ctx.queue.New()
 		ctx.startQueue()
@@ -28,14 +31,15 @@ func (ctx *JobsQueue) GetTexturesForUsername(username string) *mojang.SignedText
 	resultChan := make(chan *mojang.SignedTexturesResponse)
 	// TODO: prevent of adding the same username more than once
 	ctx.queue.Enqueue(&jobItem{username, resultChan})
+	// TODO: return nil if processing takes more than 5 seconds
 
-	return <-resultChan
+	return resultChan
 }
 
 func (ctx *JobsQueue) startQueue() {
 	go func() {
 		time.Sleep(delay)
-		for true {
+		for forever() {
 			start := time.Now()
 			ctx.queueRound()
 			time.Sleep(delay - time.Since(start))
@@ -81,6 +85,7 @@ func (ctx *JobsQueue) queueRound() {
 			}
 
 			if uuid != "" {
+				var err error
 				result, err = uuidToTextures(uuid, true)
 				if err != nil {
 					if _, ok := err.(*mojang.TooManyRequestsError); !ok {

api/mojang/queue/queue_test.go

@@ -3,211 +3,187 @@ package queue
 import (
 	"crypto/rand"
 	"encoding/base64"
-	"errors"
-	"log"
-	"testing"
-	"time"
 
 	"github.com/elyby/chrly/api/mojang"
-	testify "github.com/stretchr/testify/assert"
+
+	"github.com/stretchr/testify/mock"
+	"github.com/stretchr/testify/suite"
+	"testing"
 )
 
-func TestJobsQueue_GetTexturesForUsername(t *testing.T) {
+type MojangApiMocks struct {
-	delay = 50 * time.Millisecond
+	mock.Mock
-
-	t.Run("receive textures for one username", func(t *testing.T) {
-		assert := testify.New(t)
-
-		usernamesToUuids = createUsernameToUuidsMock(
-			assert,
-			[]string{"maksimkurb"},
-			[]*mojang.ProfileInfo{
-				{Id: "0d252b7218b648bfb86c2ae476954d32", Name: "maksimkurb"},
-			},
-			nil,
-		)
-		uuidToTextures = createUuidToTextures([]*createUuidToTexturesResult{
-			createTexturesResult("0d252b7218b648bfb86c2ae476954d32", "maksimkurb"),
-		})
-
-		queue := &JobsQueue{Storage: &NilStorage{}}
-		result := queue.GetTexturesForUsername("maksimkurb")
-
-		if assert.NotNil(result) {
-			assert.Equal("0d252b7218b648bfb86c2ae476954d32", result.Id)
-			assert.Equal("maksimkurb", result.Name)
-		}
-	})
-
-	t.Run("receive textures for few usernames", func(t *testing.T) {
-		assert := testify.New(t)
-
-		usernamesToUuids = createUsernameToUuidsMock(
-			assert,
-			[]string{"maksimkurb", "Thinkofdeath"},
-			[]*mojang.ProfileInfo{
-				{Id: "0d252b7218b648bfb86c2ae476954d32", Name: "maksimkurb"},
-				{Id: "4566e69fc90748ee8d71d7ba5aa00d20", Name: "Thinkofdeath"},
-			},
-			nil,
-		)
-		uuidToTextures = createUuidToTextures([]*createUuidToTexturesResult{
-			createTexturesResult("0d252b7218b648bfb86c2ae476954d32", "maksimkurb"),
-			createTexturesResult("4566e69fc90748ee8d71d7ba5aa00d20", "Thinkofdeath"),
-		})
-
-		queue := &JobsQueue{Storage: &NilStorage{}}
-		resultChan1 := make(chan *mojang.SignedTexturesResponse)
-		resultChan2 := make(chan *mojang.SignedTexturesResponse)
-		go func() {
-			resultChan1 <- queue.GetTexturesForUsername("maksimkurb")
-		}()
-		go func() {
-			resultChan2 <- queue.GetTexturesForUsername("Thinkofdeath")
-		}()
-
-		assert.NotNil(<-resultChan1)
-		assert.NotNil(<-resultChan2)
-	})
-
-	t.Run("query no more than 100 usernames and all left on the next iteration", func(t *testing.T) {
-		assert := testify.New(t)
-
-		usernames := make([]string, 120, 120)
-		for i := 0; i < 120; i++ {
-			usernames[i] = randStr(8)
-		}
-
-		usernamesToUuids = createUsernameToUuidsMock(assert, usernames[0:100], []*mojang.ProfileInfo{}, nil)
-
-		queue := &JobsQueue{Storage: &NilStorage{}}
-
-		scheduleUsername := func(username string) {
-			queue.GetTexturesForUsername(username)
-		}
-
-		for _, username := range usernames {
-			go scheduleUsername(username)
-			time.Sleep(50 * time.Microsecond) // Add delay to have consistent order
-		}
-
-		// Let it begin first iteration
-		time.Sleep(delay + delay/2)
-
-		usernamesToUuids = createUsernameToUuidsMock(
-			assert,
-			usernames[100:120],
-			[]*mojang.ProfileInfo{},
-			nil,
-		)
-
-		time.Sleep(delay)
-	})
-
-	t.Run("should do nothing if queue is empty", func(t *testing.T) {
-		assert := testify.New(t)
-
-		usernamesToUuids = createUsernameToUuidsMock(assert, []string{"maksimkurb"}, []*mojang.ProfileInfo{}, nil)
-		uuidToTextures = func(uuid string, signed bool) (*mojang.SignedTexturesResponse, error) {
-			t.Error("this method shouldn't be called")
-			return nil, nil
-		}
-
-		// Perform first iteration and await it finish
-		queue := &JobsQueue{Storage: &NilStorage{}}
-		result := queue.GetTexturesForUsername("maksimkurb")
-		assert.Nil(result)
-
-		// Override external API call that indicates, that queue is still trying to obtain somethid
-		usernamesToUuids = func(usernames []string) ([]*mojang.ProfileInfo, error) {
-			t.Error("this method shouldn't be called")
-			return nil, nil
-		}
-
-		// Let it to iterate few times
-		time.Sleep(delay * 2)
-	})
-
-	t.Run("handle 429 error when exchanging usernames to uuids", func(t *testing.T) {
-		assert := testify.New(t)
-
-		usernamesToUuids = createUsernameToUuidsMock(assert, []string{"maksimkurb"}, nil, &mojang.TooManyRequestsError{})
-
-		queue := &JobsQueue{Storage: &NilStorage{}}
-		result := queue.GetTexturesForUsername("maksimkurb")
-		assert.Nil(result)
-	})
-
-	t.Run("handle 429 error when requesting user's textures", func(t *testing.T) {
-		assert := testify.New(t)
-
-		usernamesToUuids = createUsernameToUuidsMock(
-			assert,
-			[]string{"maksimkurb"},
-			[]*mojang.ProfileInfo{
-				{Id: "0d252b7218b648bfb86c2ae476954d32", Name: "maksimkurb"},
-			},
-			nil,
-		)
-		uuidToTextures = createUuidToTextures([]*createUuidToTexturesResult{
-			createTexturesResult("0d252b7218b648bfb86c2ae476954d32", &mojang.TooManyRequestsError{}),
-		})
-
-		queue := &JobsQueue{Storage: &NilStorage{}}
-		result := queue.GetTexturesForUsername("maksimkurb")
-		assert.Nil(result)
-	})
 }
 
-func createUsernameToUuidsMock(
+func (o *MojangApiMocks) UsernameToUuids(usernames []string) ([]*mojang.ProfileInfo, error) {
-	assert *testify.Assertions,
+	args := o.Called(usernames)
-	expectedUsernames []string,
+	var result []*mojang.ProfileInfo
-	result []*mojang.ProfileInfo,
+	if casted, ok := args.Get(0).([]*mojang.ProfileInfo); ok {
-	err error,
+		result = casted
-) func(usernames []string) ([]*mojang.ProfileInfo, error) {
+	}
-	return func(usernames []string) ([]*mojang.ProfileInfo, error) {
+
-		assert.ElementsMatch(expectedUsernames, usernames)
+	return result, args.Error(1)
-		return result, err
+}
+
+func (o *MojangApiMocks) UuidToTextures(uuid string, signed bool) (*mojang.SignedTexturesResponse, error) {
+	args := o.Called(uuid, signed)
+	var result *mojang.SignedTexturesResponse
+	if casted, ok := args.Get(0).(*mojang.SignedTexturesResponse); ok {
+		result = casted
+	}
+
+	return result, args.Error(1)
+}
+
+type QueueTestSuite struct {
+	suite.Suite
+	Queue     *JobsQueue
+	MojangApi *MojangApiMocks
+	Iterate   func()
+
+	iterateChan chan bool
+	done        func()
+}
+
+func (suite *QueueTestSuite) SetupSuite() {
+	delay = 0
+}
+
+func (suite *QueueTestSuite) SetupTest() {
+	suite.Queue = &JobsQueue{}
+
+	suite.iterateChan = make(chan bool)
+	forever = func() bool {
+		return <-suite.iterateChan
+	}
+
+	suite.Iterate = func() {
+		suite.iterateChan <- true
+	}
+
+	suite.done = func() {
+		suite.iterateChan <- false
+	}
+
+	suite.MojangApi = new(MojangApiMocks)
+	usernamesToUuids = suite.MojangApi.UsernameToUuids
+	uuidToTextures = suite.MojangApi.UuidToTextures
+}
+
+func (suite *QueueTestSuite) TearDownTest() {
+	suite.done()
+	suite.MojangApi.AssertExpectations(suite.T())
+}
+
+func (suite *QueueTestSuite) TestReceiveTexturesForOneUsername() {
+	suite.MojangApi.On("UsernameToUuids", []string{"maksimkurb"}).Once().Return([]*mojang.ProfileInfo{
+		{Id: "0d252b7218b648bfb86c2ae476954d32", Name: "maksimkurb"},
+	}, nil)
+	suite.MojangApi.On("UuidToTextures", "0d252b7218b648bfb86c2ae476954d32", true).Once().Return(
+		&mojang.SignedTexturesResponse{Id: "0d252b7218b648bfb86c2ae476954d32", Name: "maksimkurb"},
+		nil,
+	)
+
+	resultChan := suite.Queue.GetTexturesForUsername("maksimkurb")
+
+	suite.Iterate()
+
+	result := <-resultChan
+	if suite.Assert().NotNil(result) {
+		suite.Assert().Equal("0d252b7218b648bfb86c2ae476954d32", result.Id)
+		suite.Assert().Equal("maksimkurb", result.Name)
 	}
 }
 
-type createUuidToTexturesResult struct {
+func (suite *QueueTestSuite) TestReceiveTexturesForFewUsernames() {
-	uuid   string
+	suite.MojangApi.On("UsernameToUuids", []string{"maksimkurb", "Thinkofdeath"}).Once().Return([]*mojang.ProfileInfo{
-	result *mojang.SignedTexturesResponse
+		{Id: "0d252b7218b648bfb86c2ae476954d32", Name: "maksimkurb"},
-	err    error
+		{Id: "4566e69fc90748ee8d71d7ba5aa00d20", Name: "Thinkofdeath"},
+	}, nil)
+	suite.MojangApi.On("UuidToTextures", "0d252b7218b648bfb86c2ae476954d32", true).Once().Return(
+		&mojang.SignedTexturesResponse{Id: "0d252b7218b648bfb86c2ae476954d32", Name: "maksimkurb"},
+		nil,
+	)
+	suite.MojangApi.On("UuidToTextures", "4566e69fc90748ee8d71d7ba5aa00d20", true).Once().Return(
+		&mojang.SignedTexturesResponse{Id: "4566e69fc90748ee8d71d7ba5aa00d20", Name: "Thinkofdeath"},
+		nil,
+	)
+
+	resultChan1 := suite.Queue.GetTexturesForUsername("maksimkurb")
+	resultChan2 := suite.Queue.GetTexturesForUsername("Thinkofdeath")
+
+	suite.Iterate()
+
+	suite.Assert().NotNil(<-resultChan1)
+	suite.Assert().NotNil(<-resultChan2)
 }
 
-func createTexturesResult(uuid string, result interface{}) *createUuidToTexturesResult {
+func (suite *QueueTestSuite) TestReceiveTexturesForMoreThan100Usernames() {
-	output := &createUuidToTexturesResult{uuid: uuid}
+	usernames := make([]string, 120, 120)
-	if username, ok := result.(string); ok {
+	for i := 0; i < 120; i++ {
-		output.result = &mojang.SignedTexturesResponse{Id: uuid, Name: username}
+		usernames[i] = randStr(8)
-	} else if err, ok := result.(error); ok {
-		output.err = err
-	} else {
-		log.Fatal("invalid result type passed")
 	}
 
-	return output
+	suite.MojangApi.On("UsernameToUuids", usernames[0:100]).Once().Return([]*mojang.ProfileInfo{}, nil)
+	suite.MojangApi.On("UsernameToUuids", usernames[100:120]).Once().Return([]*mojang.ProfileInfo{}, nil)
+
+	for _, username := range usernames {
+		suite.Queue.GetTexturesForUsername(username)
+	}
+
+	suite.Iterate()
+	suite.Iterate()
 }
 
-func createUuidToTextures(
+func (suite *QueueTestSuite) TestDoNothingWhenNoTasks() {
-	results []*createUuidToTexturesResult,
+	suite.MojangApi.On("UsernameToUuids", []string{"maksimkurb"}).Once().Return([]*mojang.ProfileInfo{}, nil)
-) func(uuid string, signed bool) (*mojang.SignedTexturesResponse, error) {
-	return func(uuid string, signed bool) (*mojang.SignedTexturesResponse, error) {
-		for _, result := range results {
-			if result.uuid == uuid {
-				return result.result, result.err
-			}
-		}
 
-		return nil, errors.New("cannot find corresponding result")
+	// Perform first iteration and await it finish
-	}
+	resultChan := suite.Queue.GetTexturesForUsername("maksimkurb")
+
+	suite.Iterate()
+
+	suite.Assert().Nil(<-resultChan)
+
+	// Let it to perform a few more iterations to ensure, that there is no calls to external APIs
+	suite.Iterate()
+	suite.Iterate()
+}
+
+func (suite *QueueTestSuite) TestHandle429ResponseWhenExchangingUsernamesToUuids() {
+	suite.MojangApi.On("UsernameToUuids", []string{"maksimkurb"}).Once().Return(nil, &mojang.TooManyRequestsError{})
+
+	resultChan := suite.Queue.GetTexturesForUsername("maksimkurb")
+
+	suite.Iterate()
+
+	suite.Assert().Nil(<-resultChan)
+}
+
+func (suite *QueueTestSuite) TestHandle429ResponseWhenRequestingUsersTextures() {
+	suite.MojangApi.On("UsernameToUuids", []string{"maksimkurb"}).Once().Return([]*mojang.ProfileInfo{
+		{Id: "0d252b7218b648bfb86c2ae476954d32", Name: "maksimkurb"},
+	}, nil)
+	suite.MojangApi.On("UuidToTextures", "0d252b7218b648bfb86c2ae476954d32", true).Once().Return(
+		nil,
+		&mojang.TooManyRequestsError{},
+	)
+
+	resultChan := suite.Queue.GetTexturesForUsername("maksimkurb")
+
+	suite.Iterate()
+
+	suite.Assert().Nil(<-resultChan)
+}
+
+func TestJobsQueueSuite(t *testing.T) {
+	suite.Run(t, new(QueueTestSuite))
 }
 
 // https://stackoverflow.com/a/50581165
 func randStr(len int) string {
 	buff := make([]byte, len)
-	rand.Read(buff)
+	_, _ = rand.Read(buff)
 	str := base64.StdEncoding.EncodeToString(buff)
 
 	// Base 64 can be longer than len