create internal/worker/queue test

internal/worker/queue.go

@@ -28,6 +28,7 @@ import (
 	"github.com/vdaas/vald/internal/safety"
 )
 
+// Queue represents the interface of queue.
 type Queue interface {
 	Start(ctx context.Context) (<-chan error, error)
 	Push(ctx context.Context, job JobFunc) error
@@ -45,6 +46,7 @@ type queue struct {
 	running atomic.Value
 }
 
+// NewQueue returns Queue if no error is occurred.
 func NewQueue(opts ...QueueOption) (Queue, error) {
 	q := new(queue)
 	for _, opt := range append(defaultQueueOpts, opts...) {
@@ -62,13 +64,17 @@ func NewQueue(opts ...QueueOption) (Queue, error) {
 	return q, nil
 }
 
+// Start starts execute queueing if queue is not runnnig.
+// If queue is already reunning, it returns error.
+// It returns the error channel that the queueing job return.
 func (q *queue) Start(ctx context.Context) (<-chan error, error) {
 	if q.isRunning() {
 		return nil, errors.ErrQueueIsAlreadyRunning()
 	}
 
 	ech := make(chan error, 1)
 	q.eg.Go(safety.RecoverFunc(func() (err error) {
+		defer close(ech)
 		defer close(q.outCh)
 		defer close(q.inCh)
 		defer q.running.Store(false)
@@ -102,10 +108,13 @@ func (q *queue) Start(ctx context.Context) (<-chan error, error) {
 	return ech, nil
 }
 
+// isRunning returns true when queue is already running or false when queue is not running.
 func (q *queue) isRunning() bool {
 	return q.running.Load().(bool)
 }
 
+// Push sends JobFunc to channel, which will be used for stock JobFunc, when JobFunc is not nil and queue is running.
+// If JobFunc is nil or queue is not running, Push returns error.
 func (q *queue) Push(ctx context.Context, job JobFunc) error {
 	if job == nil {
 		return errors.ErrJobFuncIsNil()
@@ -123,6 +132,8 @@ func (q *queue) Push(ctx context.Context, job JobFunc) error {
 	}
 }
 
+// Pop returns (JobFunc, nil) if the channnel, which will be used for queuing job, contains JobFunc.
+// It returns (nil ,error) if it failed to pop from the job queue.
 func (q *queue) Pop(ctx context.Context) (JobFunc, error) {
 	return q.pop(ctx, q.Len())
 }
@@ -149,6 +160,7 @@ func (q *queue) pop(ctx context.Context, retry uint64) (JobFunc, error) {
 	return q.pop(ctx, retry)
 }
 
+// Len returns the length of queue.
 func (q *queue) Len() uint64 {
 	return q.qLen.Load().(uint64)
 }