JSON test data in Selenium Java

Introduction

We use JSON test data to keep test information organized and easy to change without touching the test code.

When you want to test a web form with many input values.

When you need to run the same test with different data sets.

When you want to separate test data from test logic for easier maintenance.

When multiple testers or developers share test data in a clear format.

When you want to load test data dynamically during test execution.

Syntax

Selenium Java

{
  "key": "value",
  "number": 123,
  "array": ["item1", "item2"],
  "object": {
    "subkey": "subvalue"
  }
}

JSON uses key-value pairs inside curly braces.

Keys and string values must be in double quotes.

Examples

Simple JSON with username and password for login test.

Selenium Java

{
  "username": "testuser",
  "password": "pass123"
}

JSON with an array of user objects for testing multiple users.

Selenium Java

{
  "users": [
    {"name": "Alice", "age": 30},
    {"name": "Bob", "age": 25}
  ]
}

Sample Program

This Java Selenium test reads login data from a JSON file and uses it to fill a login form. It then checks if login succeeded by looking at the page title.

Selenium Java

import org.openqa.selenium.By;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.chrome.ChromeDriver;
import org.json.JSONObject;
import java.nio.file.Files;
import java.nio.file.Paths;

public class JsonTestDataExample {
    public static void main(String[] args) throws Exception {
        // Read JSON file content
        String content = new String(Files.readAllBytes(Paths.get("testdata.json")));
        JSONObject json = new JSONObject(content);

        // Extract test data
        String username = json.getString("username");
        String password = json.getString("password");

        // Setup WebDriver (assumes chromedriver is in system PATH)
        WebDriver driver = new ChromeDriver();
        driver.get("https://example.com/login");

        // Fill login form using JSON data
        driver.findElement(By.id("usernameInput")).sendKeys(username);
        driver.findElement(By.id("passwordInput")).sendKeys(password);
        driver.findElement(By.id("loginButton")).click();

        // Simple check: page title contains 'Dashboard' after login
        String title = driver.getTitle();
        if (title.contains("Dashboard")) {
            System.out.println("Test Passed: Login successful.");
        } else {
            System.out.println("Test Failed: Login unsuccessful.");
        }

        driver.quit();
    }
}

Important Notes

Keep JSON files well formatted for easy reading and editing.

Use meaningful keys in JSON to avoid confusion.

Always validate JSON data before using it in tests to avoid errors.

Summary

JSON test data helps separate test data from test code.

It makes tests easier to maintain and reuse with different data.

Reading JSON in Selenium Java allows dynamic and flexible testing.

Practice

1. What is the main advantage of using JSON test data in Selenium Java tests?

easy

A. It separates test data from test code for easier maintenance.

B. It makes the test run faster by compiling JSON.

C. It automatically fixes bugs in the test code.

D. It converts Java code into JSON format.

Solution

1. Step 1: Understand JSON role in testing

   JSON stores test data separately from the test code, so data changes don't require code changes.

2. Step 2: Identify benefits of separation

   This separation makes tests easier to maintain and reuse with different data sets.

3. Final Answer:

   It separates test data from test code for easier maintenance. -> Option A

4. Quick Check:

   JSON separates data and code = B [OK]

Hint: Remember: JSON holds data, not code [OK]

Common Mistakes:

• Thinking JSON speeds up test execution
• Believing JSON fixes code bugs automatically
• Confusing JSON with code format

2. Which of the following is the correct way to read a JSON file in Selenium Java using the org.json library?

easy

A. JSONObject obj = new JSONObject(new FileReader("data.json"));

B. JSONObject obj = new JSONObject("data.json");

C. JSONObject obj = new JSONObject(new FileInputStream("data.json"));

D. JSONObject obj = new JSONObject(new BufferedReader("data.json"));

Solution

1. Step 1: Check correct constructor usage

   The org.json library's JSONObject constructor accepts a Reader object to parse JSON text.

2. Step 2: Match with options

   JSONObject obj = new JSONObject(new FileReader("data.json")); uses new FileReader("data.json") which is a Reader, so it is correct.

3. Final Answer:

   JSONObject obj = new JSONObject(new FileReader("data.json")); -> Option A

4. Quick Check:

   JSONObject needs Reader input = A [OK]

Hint: Use FileReader with JSONObject constructor [OK]

Common Mistakes:

• Passing filename string directly to JSONObject
• Using InputStream instead of Reader
• Passing filename string to BufferedReader constructor

3. Given the JSON file data.json with content:

{"username": "user1", "password": "pass123"}

What will the following Java code print?

JSONObject obj = new JSONObject(new FileReader("data.json"));
System.out.println(obj.getString("username"));

medium

A. null

B. pass123

C. user1

D. Throws JSONException

Solution

1. Step 1: Parse JSON content

   The JSON has key "username" with value "user1".

2. Step 2: Call getString("username")

   This returns the string value for key "username", which is "user1".

3. Final Answer:

   user1 -> Option C

4. Quick Check:

   obj.getString("username") = "user1" [OK]

Hint: Match key names exactly to get values [OK]

Common Mistakes:

• Confusing username and password keys
• Expecting null if key exists
• Not handling JSONException properly

4. What is wrong with this Selenium Java code snippet that reads JSON test data?

JSONObject obj = new JSONObject(new FileReader("testdata.json"));
String email = obj.getString("email");
System.out.println(email);

Assuming the JSON file testdata.json does NOT contain the key email.

medium

A. It compiles but does not run.

B. It prints an empty string.

C. It returns null without error.

D. It throws a JSONException at runtime.

Solution

1. Step 1: Understand getString behavior

   Calling getString on a missing key throws JSONException in org.json library.

2. Step 2: Check code effect

   Since "email" key is missing, the code throws JSONException at runtime.

3. Final Answer:

   It throws a JSONException at runtime. -> Option D

4. Quick Check:

   Missing key getString throws exception = D [OK]

Hint: Missing JSON keys cause exceptions, not null [OK]

Common Mistakes:

• Expecting null or empty string instead of exception
• Ignoring exception handling
• Assuming code won't compile

5. You want to run a Selenium test multiple times with different user credentials stored in a JSON array like:

{"users": [{"username": "user1", "password": "pass1"}, {"username": "user2", "password": "pass2"}]}

Which approach correctly reads and uses this JSON data in Java to loop through each user?

hard

A. JSONObject users = obj.getJSONObject("users");
for (int i = 0; i < users.length(); i++) {
String username = users.getString("username");
String password = users.getString("password");
}

B. JSONArray users = obj.getJSONArray("users");
for (int i = 0; i < users.length(); i++) {
JSONObject user = users.getJSONObject(i);
String username = user.getString("username");
String password = user.getString("password");
// use username and password
}

C. String users = obj.getString("users");
for (String user : users) {
// use user
}

D. JSONArray users = obj.getJSONArray("users");
for (int i = 0; i <= users.length(); i++) {
JSONObject user = users.getJSONObject(i);
// use user
}

Solution

1. Step 1: Identify JSON array access

   The key "users" holds a JSON array, so getJSONArray("users") is correct.

2. Step 2: Loop correctly over array

   Loop from 0 to users.length() - 1, get each JSONObject, then extract username and password.

3. Step 3: Check options

   JSONArray users = obj.getJSONArray("users"); for (int i = 0; i < users.length(); i++) { JSONObject user = users.getJSONObject(i); String username = user.getString("username"); String password = user.getString("password"); // use username and password } correctly uses JSONArray, loops with i < length, and extracts data properly.

4. Final Answer:

   JSONArray users = obj.getJSONArray("users"); for (int i = 0; i < users.length(); i++) { JSONObject user = users.getJSONObject(i); String username = user.getString("username"); String password = user.getString("password"); // use username and password } -> Option B

5. Quick Check:

   JSONArray + for loop with i < length = A [OK]

Hint: Use JSONArray and loop i < length, not <= [OK]

Common Mistakes:

• Using getJSONObject instead of getJSONArray for array
• Looping with i <= length causing IndexOutOfBounds
• Treating JSON array as string