func (suite *FixedFIFOTestSuite) TestEnqueueLockSingleGR() {
	suite.NoError(suite.fifo.Enqueue(1), "Unlocked queue allows to enqueue elements")
	suite.fifo.Lock()
	err := suite.fifo.Enqueue(1)
	suite.Error(err, "Locked queue does not allow to enqueue elements")
	customError, ok := err.(*QueueError)
	suite.True(ok, "Expected error type: QueueError")
	suite.Equalf(QueueErrorCodeLockedQueue, customError.Code(), "Expected code: '%v'", QueueErrorCodeLockedQueue)
}
***************************************************************************************
** Enqueue && GetLen
***************************************************************************************
single enqueue lock verification
package goconcurrentqueue
import (
	"context"
	"sync"
	"testing"
	"time"
	"github.com/stretchr/testify/suite"
)
const (
	fixedFIFOQueueCapacity = 500
)
type FixedFIFOTestSuite struct {
	suite.Suite
	fifo *FixedFIFO
}
func (suite *FixedFIFOTestSuite) SetupTest() {
	suite.fifo = NewFixedFIFO(fixedFIFOQueueCapacity)
}
func TestFixedFIFOTestSuite(t *testing.T) {
	suite.Run(t, new(FixedFIFOTestSuite))
}