Although not recommended by the celery documentation
CELERY_TASK_ALWAYS_EAGER = True option allows E2E testing where celery task is called inside a function with delay() method.

The following code of get_queue_length gives queue length as zero all the time but when I run the same set of command in Django shell it works fine and gives total number of object in the queue

In Celery I want my tasks to run sequentially! As they dependent on each other! But the main issue as follows: Job_1 was submitted which has two tasks: Task_1_1 and Task_2_1. Now, it works perfectly fine. However, if Task_1_1 was running and Job_2 was submitted, Task_1_2 will run after Task_1_1 and not Task_2_1! After Task_1_2 finishes, Task_2_1 and Task_2_2 will run! But I want Job_1 to finish completely before jumping to Job_2!