Quality assurance interview questions

An online shop sells pet food and accessories. Customers can choose goods and conclude their orders on their website. The order is processed according to these rules:

• A customer enters his or her order and clicks SUBMIT. Depending on its total value, the order is set to either of the following states:
  • APPROVED if the value is less than or equal to $100.
  • PENDING if the value is greater than $100 and the shop's personnel have to verify the validity of the online payment.
• For PENDING orders, shop personnel can click one of the following:
  • APPROVE if the payment is confirmed, thereby setting the order to the state of APPROVED.
  • CANCEL if the payment is invalid, thereby setting the order to the state of CANCELED.
• For orders in an APPROVED state, the shop personnel choose the SHIP action after the goods are actually sent, thereby setting the order to a state of SHIPPED.

Prepare the optimal (effective and efficient) set of test cases, each containing either a complete or partial state lifecycle, required to test this system.

An informational Interest rate calculator for a fixed term deposit needs to be tested. For a given deposit amount and the client’s age, the calculator shows the annual interest rate.

The following rules apply:

• The minimum deposit amount is $100.
• The maximum deposit amount is $10,000.
• The annual interest rate depends on the deposit amount as follows:

  Deposit amount	Annual interest rate
  $100 - $999	1.0%
  $1,000 - $4,999	1.3%
  $5,000 - $10,000	1.5%

• Only adults (aged 18 and older) are eligible to open a term deposit account.
• Clients aged 60 and older have a fixed interest rate of 2%.

Define the optimal (effective and efficient) set of boundary test cases for a system that calculates the terms deposit interest.

Your team is developing software for a thermostat controller that does the following:

• The target temperature is fixed at 23°C.
• The environment temperature is measured in this range: -50°C to 50°C.
• The thermostat has a heating switch for turning the heating function on and off.

The rules for the heating control are as follows:

• If the heating switch is on and the measured temperature is equal or higher than the target temperature, the heating should be turned off. If the measured temperature is lower than target temperature, the heating should be turned on.
• If the heating switch is off, the heating is turned off regardless of the measured and target temperatures unless the measured temperature falls below 5°C. At that point the heating should be turned on to avoid having the water in the heating system freeze.

Define the optimal (effective and efficient) set of boundary test cases to adequately test the thermostat controller.