fix race conditions in TestTelegramConfirmedRequest

There were two different race conditions between logic in TestTelegramConfirmedRequest
and TelegramAPIMock.GetUpdatesFunc and TelegramAPIMock.SendFunc:
* GetUpdatesFunc may start before token was fetched,
then it produces empty telegramUpdate response, which causes assertions in SendFunc to fail.
* When token becomes used and removed from wait queue after successful login completion,
then GetUpdatesFunc may be still called and new telegram update is created for same token.
This breaks telegram update processing logic,
and SendFunc gets called with the error parameter, which also breaks assertions.

provider/telegram_test.go

@@ -89,22 +89,37 @@ func TestTelegramUnconfirmedRequest(t *testing.T) {
 
 func TestTelegramConfirmedRequest(t *testing.T) {
 	var servedToken string
-	var mu sync.Mutex
+
+	// is set when token becomes used,
+	// no sync is required because only a single goroutine in TelegramHandler.Run() reads and writes it
+	var tokenAlreadyUsed bool
+
+	var wgToken sync.WaitGroup
+	wgToken.Add(1)
+	defer func() {
+		if t.Failed() && servedToken == "" {
+			wgToken.Done() // for the case when test fails before token is generated
+		}
+	}()
 
 	m := &TelegramAPIMock{
 		GetUpdatesFunc: func(ctx context.Context) (*telegramUpdate, error) {
-			var upd telegramUpdate
+			wgToken.Wait()
 
-			mu.Lock()
-			defer mu.Unlock()
-			if servedToken != "" {
-				resp := fmt.Sprintf(getUpdatesResp, servedToken)
+			if tokenAlreadyUsed || t.Failed() {
+				return nil, fmt.Errorf("token %s has been already used", servedToken)
+			}
 
-				err := json.Unmarshal([]byte(resp), &upd)
-				if err != nil {
-					t.Fatal(err)
-				}
+			var upd telegramUpdate
+			resp := fmt.Sprintf(getUpdatesResp, servedToken)
+			err := json.Unmarshal([]byte(resp), &upd)
+			if err != nil {
+				t.Fatal(err)
 			}
+
+			// token is served only once
+			tokenAlreadyUsed = true
+
 			return &upd, nil
 		},
 		AvatarFunc: func(ctx context.Context, userID int) (string, error) {
@@ -147,10 +162,10 @@ func TestTelegramConfirmedRequest(t *testing.T) {
 	err := json.Unmarshal(w.Body.Bytes(), &resp)
 	assert.NoError(t, err)
 	assert.Equal(t, "my_auth_bot", resp.Bot)
+	assert.NotEmpty(t, resp.Token)
 
-	mu.Lock()
 	servedToken = resp.Token
-	mu.Unlock()
+	wgToken.Done()
 
 	// Check the token confirmation
 	assert.Eventually(t, func() bool {

v2/provider/telegram_test.go

@@ -89,22 +89,36 @@ func TestTelegramUnconfirmedRequest(t *testing.T) {
 
 func TestTelegramConfirmedRequest(t *testing.T) {
 	var servedToken string
-	var mu sync.Mutex
+	// is set when token becomes used,
+	// no sync is required because only a single goroutine in TelegramHandler.Run() reads and writes it
+	var tokenAlreadyUsed bool
+
+	var wgToken sync.WaitGroup
+	wgToken.Add(1)
+	defer func() {
+		if t.Failed() && servedToken == "" {
+			wgToken.Done() // for the case when test fails before token is generated
+		}
+	}()
 
 	m := &TelegramAPIMock{
 		GetUpdatesFunc: func(ctx context.Context) (*telegramUpdate, error) {
-			var upd telegramUpdate
+			wgToken.Wait()
 
-			mu.Lock()
-			defer mu.Unlock()
-			if servedToken != "" {
-				resp := fmt.Sprintf(getUpdatesResp, servedToken)
+			if tokenAlreadyUsed || t.Failed() {
+				return nil, fmt.Errorf("token %s has been already used", servedToken)
+			}
 
-				err := json.Unmarshal([]byte(resp), &upd)
-				if err != nil {
-					t.Fatal(err)
-				}
+			var upd telegramUpdate
+			resp := fmt.Sprintf(getUpdatesResp, servedToken)
+			err := json.Unmarshal([]byte(resp), &upd)
+			if err != nil {
+				t.Fatal(err)
 			}
+
+			// token is served only once
+			tokenAlreadyUsed = true
+
 			return &upd, nil
 		},
 		AvatarFunc: func(ctx context.Context, userID int) (string, error) {
@@ -147,10 +161,10 @@ func TestTelegramConfirmedRequest(t *testing.T) {
 	err := json.Unmarshal(w.Body.Bytes(), &resp)
 	assert.NoError(t, err)
 	assert.Equal(t, "my_auth_bot", resp.Bot)
+	assert.NotEmpty(t, resp.Token)
 
-	mu.Lock()
 	servedToken = resp.Token
-	mu.Unlock()
+	wgToken.Done()
 
 	// Check the token confirmation
 	assert.Eventually(t, func() bool {