Unit test running forever for call back method in C#

Question

Following is the method to receive the message on RabbitMq Queue. Method works fine but the unit testing this method has problem mentioned below

      public void GetMessage(Action<string> action)
    {
        //create a connection factory
        var factory = new ConnectionFactory();

        if (_connectionString != null)
        {
            //assign connection string of rabbitmq
            factory.Uri = new Uri(_connectionString);
        }

        //create connection and channel from connectionfactory
        using (var connection = factory.CreateConnection())
        using (var channel = connection.CreateModel())
        {

            //declare the queque on the channel
            channel.QueueDeclare(queue: _queque,
                                 durable: false,
                                 exclusive: false,
                                 autoDelete: false,
                                 arguments: null);

            //create consumer using the channel
            var consumer = new EventingBasicConsumer(channel);
            consumer.Received += (model, ea) =>
            {
                //When message is recieved on the consumer this will be triggered
                var body = ea.Body.ToArray();
                _message = Encoding.UTF8.GetString(body);

                //call the method passed by the caller method
                action(_message);
            };

            //add the consumer on this channel
            channel.BasicConsume(queue: _queque,
                                 autoAck: true,
                                 consumer: consumer);

            Console.ReadLine();
        }

    }

How to write a unit test test above message. Below unit test loading forever inside the call back method and the execution never goes to Assert.Equal line.

      [Fact]
    public async Task AddMessageAsync_ShouldAddToQueue()
    {
        //Arrange
        string messageToSend = "Test";
        string recievedMessage = null;
        var queue = GetQueueManager();

        queue.Message = messageToSend;

        await queue.AddMessageAsync();

        //Act
        queue.GetMessage((string message) =>
        {
            //Hit here and recieved the message but does not exist from this method
            recievedMessage = message;
        });

        //Assert
        Assert.Equal(messageToSend, recievedMessage);
    }