Database Testing Using Java Selenium and TestNG

Database testing is very important in software testing because every application has a database that stores data. In this article, we will learn about Database testing Using Java Selenium and TestNG.

What is Database Testing?

Database testing is a type of software testing, which is used to check the estimate of data integrity and consistency under test and also examine the schema, table, data, etc of a database. For example, suppose there is data stored in a database and data is entered into an application through the graphical user interface, matching the entered data and stored data is an example of database testing.

How to Perform Database Testing Using Selenium and TestNG?

To start database testing, the initial step is to establish a connection with the database. Let’s learn how to do that.

How to Connect to the database?

If we want to perform Database testing then the very first thing we have to do is to Connect to the database. Now let’s understand how to Connect to the database. To connect to a database from a Java application, we use JDBC (Java Database Connectivity), a Java API for connecting and executing SQL queries on a database. These are some steps to connect with the database using JDBC.

Step 1: Load the JDBC Driver: Load the JDBC Driver: With the help of the Class.forName() method, we will load the JDBC Driver for our database. This is the very first step.

Class.forName(“com.mysql.cj.jdbc.Driver”);

Step 2: Establish a Connection: We will use DriverManager.getConnection(databaseURL, user, password) method to establish the connection to the database. Here URL, user, and password are the parameters that are being passed into the given method.

Stringdatabase URLL = “jdbc:mysql://localhost:3306/org”; //Database URL – Contains jdbc , localhost, port & org is name of database

String user = “root”; // username

String password = “root@123”; // password

connection = DriverManager.getConnection(databaseURL, user, password);

Step 3: Execute SQL Queries: Once the connection is set up, we can start running SQL commands. These commands can be things like fetching data (SELECT), adding new data (INSERT), updating existing data (UPDATE), or removing data (DELETE).

Step 4: Process the Results: If our SQL query gives back some data (like with a SELECT query), we can get that data from the result set and work with it however we want.

Step 5: Close the Connection: At last, we will close the database connection using the connection.close().

Now Let’s Understand how to perform Database Testing Using Java Selenium and TestNG through an example.

Example of Database Testing Using Selenium TestNG

Step 1: Open the Eclipse IDE.

Step 2: Create a Java Project

Java

package com.geeksforgeeks.test;

import org.testng.annotations.AfterClass;
import org.testng.annotations.BeforeClass;
import org.testng.annotations.Test;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class DatabaseTesting {

    private Connection connection;
    private Statement statement;
    private ResultSet resultSet;

    @BeforeClass
    public void establishDatabaseConnection() throws ClassNotFoundException, SQLException  {
         // Database connection details
        String databaseURL = "jdbc:mysql://localhost:3306/org";
        String user = "root";
        String password = "root@123";
        
     // Load the MySQL JDBC driver and establish connection
         Class.forName("com.mysql.cj.jdbc.Driver");
         System.out.println("Connecting to Database");
         connection = DriverManager.getConnection(databaseURL, user, password);
         
      // Check if the connection is successful
         if (connection == null) {
                System.out.println("Database Connection Failed");
            }else {
                System.out.println("Database Connection Successful");
            }
        }
    

    @Test
    public void retrieveworkerFromDatabase() {
        try {
            
            // SQL query to retrieve worker from the database
            String query = "SELECT * FROM worker";
            statement = connection.createStatement();
            resultSet = statement.executeQuery(query);
            
         // Iterate through the result set and print worker details
            while (resultSet.next()) {
                int empId = resultSet.getInt("WORKER_ID");
                String empFirstName = resultSet.getString("FIRST_NAME");
                String empLastName = resultSet.getString("LAST_NAME");
                int salary = resultSet.getInt("SALARY");
                String department = resultSet.getString("DEPARTMENT");
                
             // Print worker details
                System.out.println("Employee ID: " + empId + ", First Name: " + empFirstName + ", Last Name: " 
+ empLastName + ", Salary: " + salary + ", Department: " + department);

            }
        } catch (Exception error) {
            error.printStackTrace();
        }
    }

    @AfterClass
    public void closeDatabaseConnection() {
        
        // Close the database connection
        if (connection != null) {
            try {
                System.out.println("Closing Database Connection...");
                connection.close();
            } catch (Exception error) {
                error.printStackTrace();
            }
        }
    }
}

Explanation:

This Java class DatabaseTesting is a TestNG test class that shows how to connect to a MySQL database and retrieve data using JDBC. Let’s explain this code.

• Imports
  • Import necessary classes from TestNG and JDBC packages.
• Class Declaration:
  • The class DatabaseTesting is declared.
• Instance Variables:
  • We declare three things as private instance variables: connection, statement, and resultSet. These are used for connecting to the database, running SQL queries, and handling the results of those queries.
• @BeforeClass Method – establishDatabaseConnection():
• • This function is marked with @BeforeClass, meaning it runs before any test methods in the class. It sets up a database connection by loading the MySQL JDBC driver (Class.forName()) and gets a connection using DriverManager.getConnection(). It then checks if the connection is successful and prints relevant messages.
• @Test Method – retrieveworkerFromDatabase():
  • This function is marked with @Test, showing it’s a test method. It gets information from the worker table in the database by running a SQL query (SELECT * FROM worker). Then, it goes through each row of the result and prints details about each worker, like their employee ID, first name, last name, salary, and department.
• @AfterClass Method – closeDatabaseConnection():
  • This function is marked with @AfterClass, meaning it runs after all the test methods in the class are done. It closes the connection to the database (connection.close()) to free up resources.
• Exception Handling:
  • Exceptions such as ClassNotFoundException, SQLException, and Exception are caught and their stack traces are printed for debugging purposes.

Step 3: Run this TestNG test Class. Right click on the DatabaseTesting Class, move the cursor down to Run As, and then click on the 1 TestNG Suite.

Output:

Output