Gomock not working for sending data to cockroach DB - unit-testing

Question

I am writing a unit test for a function which calls a goroutine to send data to cockroach db. I am trying to mock the call to cockroach db which doesn't seem to work.The test case results in time out in the exact same manner as it would have if there was no mocking done for sendBatch to cockroach db.
here are the functions:
func DrainQueue() {
for range time.Tick(time.Second * time.Duration(1)) {
if q.Length() > 0 {
var queuedItems []interface{}
// Read the queue up to the size specified.
for qlen := 0; qlen < QueueSize && q.Length() > 0; qlen++ {
itemFromQueue := q.Pop()
queuedItems = append(queuedItems, itemFromQueue)
}
logging.Debug("Sending to cockroachDB...")
go SendToCockRoachDB(queuedItems...)
queuedItems = nil
}
}
}
func SendToCockRoachDB(toSend ...interface{}) ([][][]byte, int64, error) {
var nor int64
var qErr error
var rows pgx.Rows
var results = make([][][]byte, 0)
batch := &pgx.Batch{}
for _, item := range toSend {
qs := item.(*QueryStruct)
batch.Queue(qs.Query, qs.Items...)
}
// Send to cockroachDB
br := dbConn.dbpool.SendBatch(dbConn.ctx, batch)
defer br.Close()
rows, qErr = br.Query()
if qErr != nil {
return nil, 0, qErr
}
for rows.Next() {
results = append(results, rows.RawValues())
}
nor += rows.CommandTag().RowsAffected()
if nor > 0 {
logging.Log.Printf("Inserted: %d rows", nor)
}
return results, nor, qErr
}
The test function I have created works like this:
func TestDrainQueue(t *testing.T) {
var results = make([][][]byte, 0)
var nor int64 = 0
controller := gomock.NewController(t)
defer controller.Finish()
mockSendBatch := Mocks.NewMockValues(controller)
mockSendBatch.EXPECT().SendToCockRoachDB(mockSendBatch).Return(results, nor, nil)
DrainQueue()
}
I have created a mock function using gomock for SendToCockRoachDB and have called it in the unit test