Why Use CSV Files for Test Automation?
CSV files are widely used in testing because they are:
Simple and human-readable
Easy to generate and maintain
Compatible with Excel and other tools
Great for data-driven tests
Using CSV allows you to separate test data from test scripts, making tests reusable and maintainable.
🧰 1. Add a CSV Library (Optional)
Java can handle CSVs using core classes (BufferedReader, FileReader), but libraries simplify the process:
OpenCSV (most popular)
Apache Commons CSV
Maven dependency for OpenCSV:
<dependency>
<groupId>com.opencsv</groupId>
<artifactId>opencsv</artifactId>
<version>5.8</version>
</dependency>
📂 2. Sample CSV File
Example testdata.csv:
username,password,role
admin,Admin123,ADMIN
user1,User123,USER
guest,Guest123,GUEST
🧑💻 3. Reading CSV Data in Java
Using OpenCSV:
import com.opencsv.CSVReader;
import java.io.FileReader;
import java.util.List;
public class CsvReaderExample {
public static void main(String[] args) throws Exception {
CSVReader reader = new CSVReader(new FileReader("src/test/resources/testdata.csv"));
List<String[]> records = reader.readAll();
for (String[] record : records) {
System.out.println("Username: " + record[0] + ", Password: " + record[1] + ", Role: " + record[2]);
}
reader.close();
}
}
Using Java Core Classes:
import java.io.BufferedReader;
import java.io.FileReader;
public class CsvReaderCore {
public static void main(String[] args) throws Exception {
BufferedReader br = new BufferedReader(new FileReader("src/test/resources/testdata.csv"));
String line;
while ((line = br.readLine()) != null) {
String[] data = line.split(",");
System.out.println("Username: " + data[0] + ", Password: " + data[1] + ", Role: " + data[2]);
}
br.close();
}
}
📝 4. Writing to CSV
Using OpenCSV:
import com.opencsv.CSVWriter;
import java.io.FileWriter;
public class CsvWriterExample {
public static void main(String[] args) throws Exception {
CSVWriter writer = new CSVWriter(new FileWriter("output.csv"));
String[] header = { "username", "password", "role" };
writer.writeNext(header);
String[] record1 = { "admin", "Admin123", "ADMIN" };
String[] record2 = { "user1", "User123", "USER" };
writer.writeNext(record1);
writer.writeNext(record2);
writer.close();
}
}
🔗 5. Using CSV Data in Selenium Tests
CSV files are great for data-driven testing.
Example with Selenium:
import org.openqa.selenium.By;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.chrome.ChromeDriver;
import com.opencsv.CSVReader;
import java.io.FileReader;
public class LoginTestCSV {
public static void main(String[] args) throws Exception {
WebDriver driver = new ChromeDriver();
driver.get("https://example.com/login");
CSVReader reader = new CSVReader(new FileReader("src/test/resources/testdata.csv"));
String[] record;
reader.readNext(); // Skip header
while ((record = reader.readNext()) != null) {
String username = record[0];
String password = record[1];
driver.findElement(By.id("username")).clear();
driver.findElement(By.id("username")).sendKeys(username);
driver.findElement(By.id("password")).clear();
driver.findElement(By.id("password")).sendKeys(password);
driver.findElement(By.id("loginButton")).click();
// Add assertions here
}
reader.close();
driver.quit();
}
}
🧪 6. Using CSV with TestNG DataProvider
@DataProvider(name = "loginData")
public Object[][] readCsvData() throws Exception {
CSVReader reader = new CSVReader(new FileReader("src/test/resources/testdata.csv"));
List<String[]> records = reader.readAll();
reader.close();
Object[][] data = new Object[records.size() - 1][2]; // exclude header
for (int i = 1; i < records.size(); i++) {
data[i - 1][0] = records.get(i)[0]; // username
data[i - 1][1] = records.get(i)[1]; // password
}
return data;
}
@Test(dataProvider = "loginData")
public void loginTest(String username, String password) {
driver.get("https://example.com/login");
driver.findElement(By.id("username")).sendKeys(username);
driver.findElement(By.id("password")).sendKeys(password);
driver.findElement(By.id("loginButton")).click();
}
This makes your Selenium tests fully data-driven using CSV files.
⚡ 7. Best Practices
Keep CSV files in src/test/resources.
Use a header row to identify columns.
Use OpenCSV for easier parsing and writing.
Avoid hardcoding file paths; use Paths.get() for portability.
Combine with TestNG/JUnit DataProvider for scalable tests.
Use separate CSV files for different test scenarios.
🎯 Summary
CSV is simple, flexible, and widely used for test automation.
OpenCSV makes reading/writing CSVs in Java easy.
Use CSV for data-driven Selenium tests.
Combine with TestNG/JUnit for clean, maintainable, and scalable automated tests.
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Read More
Using JSON for Test Data in Java Selenium
Writing Test Results into Excel Files in Selenium
Reading Test Data from Excel using Apache POI
🔌 Data Handling and Advanced Concepts
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