Provide an example of functional and non-functional testing using a ballpoint pen as an example.

Functional testing checks whether the product meets the specified requirements and performs its functions.

Example for a ballpoint pen:

• Checking if the pen writes on paper.
• Checking if the ink does not leak.
• Checking if the mechanism for extending the pen tip works.

Non-functional testing evaluates the characteristics of the product that are not directly related to its functions.

Example for a ballpoint pen:

• Testing the comfort of holding the pen (ergonomics).
• Checking the drying time of the ink.
• Assessing the durability of the pen tip (how many pages can be written).
• Testing resistance to temperature conditions or moisture.

Thus, functional testing answers the question "What does the pen do?", while non-functional testing answers "How does it do it?" and "How well?".