JUnit अभिकथन और निष्पादन

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

public class MathUtilsTest {

    // A simple method to test
    int add(int a, int b) {
        return a + b;
    }

    @Test
    void testAddMethod() {
        // Expected result: 5
        int expected = 5;
        // Actual result from our method
        int actual = add(2, 3);
        
        // Assert that expected and actual are the same
        assertEquals(expected, actual, "2 + 3 should be 5");
    }
}

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

public class NumberCheckerTest {

    // A simple method to test
    boolean isPositive(int number) {
        return number > 0;
    }

    @Test
    void testIsPositive() {
        int num = 10;
        // Assert that num is positive
        assertTrue(isPositive(num), num + " should be positive");
    }
}

import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.assertNotNull;
import static org.junit.jupiter.api.Assertions.assertNull;

public class UserServiceTest {

    // Dummy method simulating fetching a user
    String getUserById(int id) {
        if (id == 1) {
            return "Alice"; // User found
        }
        return null; // User not found
    }

    @Test
    void testExistingUser() {
        String user = getUserById(1);
        assertNotNull(user, "User with ID 1 should exist");
    }

    @Test
    void testNonExistingUser() {
        String user = getUserById(99);
        assertNull(user, "User with ID 99 should not exist");
    }
}