Do you write tests? What types of testing do you use?

Yes, I always write tests. Depending on the task, I use different types of testing:

• Unit tests — check individual methods or classes. They allow for quick detection of errors at the code level.
• Integration tests — verify the interaction between components.
• Functional tests — test the application's operation from the user's perspective.
• Regression tests — ensure that new changes haven't broken existing functionality.

In Java, I usually use JUnit for unit tests and Mockito for mocking dependencies. Here's a simple example of a unit test in JUnit 5:

import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.*;

class CalculatorTest {
    @Test
    void additionTest() {
        Calculator calc = new Calculator();
        assertEquals(5, calc.add(2, 3));
    }
}

Testing helps improve the reliability and quality of the code.