JSON test data in Selenium Java - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of parsing this JSON string in Java?

Given the following JSON string and Java code snippet using org.json library, what will be the output printed?

Selenium Java

String jsonString = "{\"name\": \"Alice\", \"age\": 30, \"active\": true}";
JSONObject obj = new JSONObject(jsonString);
System.out.println(obj.getString("name") + ", " + obj.getInt("age") + ", " + obj.getBoolean("active"));

A Alice, 30, true

B Alice, 30, false

C 30, Alice, true

D Throws JSONException

💡 Hint

Remember to match the JSON keys with the correct getter methods.

The JSON string contains keys 'name', 'age', and 'active' with values 'Alice', 30, and true respectively. The code correctly retrieves these values and prints them in order.

❓ assertion

intermediate

Which assertion correctly verifies the 'status' field in JSON response?

You receive a JSON response: {"status":"success","code":200}. Which JUnit assertion correctly checks that the 'status' field equals 'success'?

A assertFalse(jsonObject.getBoolean("status"));

B assertTrue(jsonObject.getInt("status") == 200);

C assertEquals("success", jsonObject.getString("status"));

D assertNull(jsonObject.getString("status"));

💡 Hint

Check the data type of the 'status' field in JSON.

The 'status' field is a string with value 'success'. Option C correctly asserts this. Other options either use wrong data types or wrong assertions.

❓ locator

advanced

Identify the best locator to find a JSON data-driven test element

You have a web page that dynamically loads test data from JSON into elements with data-test-id attributes. Which Selenium locator is best to find the element with data-test-id='user-123'?

A By.id("user-123")

B By.xpath("//div[@data-test-id='user-123']")

C By.className("user-123")

D By.cssSelector("[data-test-id='user-123']")

💡 Hint

Use attribute selectors for custom data attributes.

The best locator uses CSS selector for the attribute data-test-id with value 'user-123'. Option D works but is less efficient. Options A and D do not match the attribute.

🔧 Debug

advanced

Why does this JSON parsing code throw an exception?

Consider this Java code snippet: String jsonString = "{\"id\": 101, \"name\": null}"; JSONObject obj = new JSONObject(jsonString); String name = obj.getString("name"); Why does obj.getString("name") throw an exception?

Selenium Java

String jsonString = "{\"id\": 101, \"name\": null}";
JSONObject obj = new JSONObject(jsonString);
String name = obj.getString("name");

A Because the 'name' key has a null value, getString throws JSONException

B Because getString cannot be used with integers

C Because jsonString is not valid JSON

D Because 'name' key is missing in JSON

💡 Hint

Check how org.json handles null values in JSON objects.

The 'name' key exists but its value is null. org.json's getString method throws JSONException if the value is null. To avoid this, use optString or check for null.

❓ framework

expert

How to integrate JSON test data with Selenium tests in Java?

Which approach best integrates external JSON test data into Selenium Java tests for data-driven testing?

A Hardcode JSON strings inside Selenium test methods and parse inline

B Read JSON file using Jackson or Gson, parse into POJOs, then use TestNG DataProvider to supply test data

C Use Selenium WebDriver to fetch JSON from web page and parse it during test execution

D Convert JSON to XML manually and use XML parsers for test data

💡 Hint

Consider maintainability and separation of test data from test code.

Option B is best practice: external JSON files parsed by libraries like Jackson or Gson, then used with TestNG DataProvider for clean, maintainable data-driven tests. Other options are inefficient or error-prone.

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