Testing an Elevator Made Easy

This is one of my favorite questions for the testing interviews. Those who give me most of the scenarios are most likely to get through. Well, after posting this in my blog I may change my question. But I felt very compelling to share this question with the community.

So, here is the question: Give me some scenarios that you will be testing for an elevator.

(I recommend you read this post till the end)

Most of the prospective team members come-up with following scenarios:

1. Door Open/ Close functionality of the elevator should work fine

2. The elevator takes you to the desired floor, based on the button you press for the respective floor

4. Elevator arrives with a suitable buzzer (eg. Third Floor)

5. Elevator door opens/ closes within the specified time

6. Elevator remains at the last destination till there is any trigger to call the elevator to any floor

7. If there is a stop button the elevator, it should stop the elevator at the nearest floor

8. The speed of the elevator is as per the specification

Most of the candidates are able to answer till this point. If I ask for more they may/ may not come up with following scenarios.

9. When power goes off the elevator should stop immediately, if there is no power back-up and one of the following should happen:

(i) There should be an emergency light in the elevator

(ii) There should be a buzzer to raise an alarm to the security

(iii) There can be a phone and should be functional

(iv) If there is no emergency light or phone, there will be darkness in the elevator. So the buzzer should glow in the dark

Huh… What next?

10. Verify the capacity of the elevator in terms of weight (for example 1000 Kg). One of the following should happen:

(i) The elevator should not go up/ down if the weight limit is surpassed

(ii) A buzzer should ring to raise the alarm that weight limit has crossed

That’s it! No, not yet. I look for even more.

11. You must have noticed that the manufacturer specifies the capacity of persons (for example 15 Persons). Why is that? Any guess?

Is it because of space issue? No.

Did manufacturer guess the average weight of the person and specified based on that the cumulative weight and person’s capacity? Well, no. Because the moment it crosses the weight limit, the elevator won’t move. So you need not do any mental calculation.

Ok. No more rewards for guessing.

There is limited air available for breathing and the ventilation is very limited. People boarded in the elevator will be breathing and it might choke the container if more number of people than specified is boarded. The situation may become even worse when the power goes off and those people are stuck in it.

That’s it! Please let me know if you come across more such scenarios.