Performance testing tools overview in Testing Fundamentals - Build an Automation Script

Basic Load Test Using Apache JMeter

Preconditions (2)

Step 1: Open Apache JMeter

Step 2: Create a new Test Plan

Step 3: Add a Thread Group with 10 users and loop count 5

Step 4: Add an HTTP Request sampler targeting the test environment URL

Step 5: Add a View Results Tree listener

Step 6: Start the test

Step 7: Observe the results in the listener

✅ Expected Result: The test completes without errors, and the response times are recorded in the listener showing successful requests

Automation Requirements - Apache JMeter

Assertions Needed:

Verify all HTTP requests return status code 200

Verify average response time is below 2 seconds

Best Practices:

Use Thread Group to simulate concurrent users

Add assertions to validate response status

Use listeners to capture and analyze results

Avoid hardcoding URLs; use variables for flexibility

Automated Solution

Testing Fundamentals

Test Plan:
  Thread Group:
    Number of Threads (users): 10
    Loop Count: 5
    HTTP Request:
      Server Name or IP: example.com
      Path: /api/test
    Response Assertion:
      Field to Test: Response Code
      Pattern Matching Rules: Equals
      Patterns to Test: 200
    Summary Report Listener

# Explanation:
# This JMeter test plan simulates 10 users sending 5 requests each to the target URL.
# The Response Assertion checks that each HTTP response returns status code 200.
# The Summary Report Listener collects metrics including average response time.
# This setup helps verify the server handles load and responds correctly within expected time.

This test plan uses Apache JMeter to simulate multiple users accessing a web service.

The Thread Group controls how many users and how many times they send requests.

The HTTP Request sampler defines the target URL to test.

The Response Assertion ensures the server responds with status code 200, meaning success.

The Summary Report Listener collects performance data like response times.

This setup helps check if the server can handle the load and respond quickly.

Common Mistakes - 3 Pitfalls

Not adding assertions to verify response status codes

Using too few users or loops, not simulating real load

Hardcoding URLs directly in HTTP Request sampler

Bonus Challenge

Now add data-driven testing with 3 different URLs to test performance on multiple endpoints

Show Hint

Practice

1. Which of the following best describes the main purpose of performance testing tools?

easy

A. To check software speed and stability under load

B. To find spelling mistakes in the code

C. To design the user interface

D. To manage project tasks and deadlines

Solution

1. Step 1: Understand the role of performance testing tools

   Performance testing tools are used to measure how software behaves when many users use it at the same time.

2. Step 2: Match the description to the correct purpose

   Checking speed and stability under load matches the main goal of these tools.

3. Final Answer:

   To check software speed and stability under load -> Option A

4. Quick Check:

   Performance testing = speed and stability check [OK]

Hint: Performance tools test speed and load, not UI or spelling [OK]

Common Mistakes:

• Confusing performance testing with UI design
• Thinking performance tools check code spelling
• Mixing project management with testing tools

2. Which of the following is a popular open-source performance testing tool?

easy

A. Excel

B. Photoshop

C. JMeter

D. Slack

Solution

1. Step 1: Identify known performance testing tools

   JMeter is a widely used open-source tool for performance testing.

2. Step 2: Eliminate unrelated software

   Photoshop is for image editing, Excel for spreadsheets, Slack for communication, so they are not performance testing tools.

3. Final Answer:

   JMeter -> Option C

4. Quick Check:

   JMeter = open-source performance tool [OK]

Hint: Remember JMeter is for testing, not design or communication [OK]

Common Mistakes:

• Choosing tools unrelated to testing
• Confusing general software with testing tools
• Not recognizing JMeter as a testing tool

3. Consider this code snippet using Locust for performance testing:

from locust import HttpUser, task, between

class WebsiteUser(HttpUser):
    wait_time = between(1, 3)

    @task
    def load_main(self):
        self.client.get("/")

What does this test simulate?

medium

A. A user sending POST requests to update data

B. A user repeatedly requesting the home page with pauses between 1 to 3 seconds

C. A user logging in once and then stopping

D. A user uploading files continuously without delay

Solution

1. Step 1: Analyze the Locust test class

   The class WebsiteUser simulates a user who waits between 1 and 3 seconds before each task.

2. Step 2: Understand the task method

   The load_main task sends a GET request to the home page repeatedly with pauses.

3. Final Answer:

   A user repeatedly requesting the home page with pauses between 1 to 3 seconds -> Option B

4. Quick Check:

   Locust task with wait_time = repeated GET with delay [OK]

Hint: Look for wait_time and GET to find user behavior [OK]

Common Mistakes:

• Assuming POST requests instead of GET
• Ignoring the wait_time causing pauses
• Thinking the user uploads files or logs in

4. You wrote a Gatling test script but it fails to run. The error says: "Could not find simulation class". What is the most likely cause?

medium

A. The test server is down

B. The Gatling tool is not installed

C. The internet connection is slow

D. The simulation class name does not match the file name or is missing

Solution

1. Step 1: Understand the error message

   "Could not find simulation class" means Gatling cannot locate the test class to run.

2. Step 2: Identify common causes

   This usually happens if the class name is wrong, missing, or does not match the file name.

3. Final Answer:

   The simulation class name does not match the file name or is missing -> Option D

4. Quick Check:

   Class name mismatch = simulation class not found [OK]

Hint: Check class and file names match exactly [OK]

Common Mistakes:

• Blaming server or internet issues for class errors
• Ignoring naming conventions in Gatling
• Assuming Gatling is not installed without checking

5. You want to test a web app's performance under heavy load using JMeter. Which approach is best to simulate many users realistically?

hard

A. Create a Thread Group with many threads and add realistic HTTP requests with timers

B. Run a single HTTP request repeatedly without delay

C. Use JMeter only to check spelling errors in the app

D. Test only the database without simulating user actions

Solution

1. Step 1: Understand how JMeter simulates users

   JMeter uses Thread Groups to simulate multiple users (threads) performing actions.

2. Step 2: Identify realistic load simulation

   Adding HTTP requests with timers mimics real user behavior with pauses and varied actions.

3. Final Answer:

   Create a Thread Group with many threads and add realistic HTTP requests with timers -> Option A

4. Quick Check:

   Thread Group + timers = realistic user load [OK]

Hint: Use many threads and timers for real user simulation [OK]

Common Mistakes:

• Running single requests without delay
• Using JMeter for non-performance tasks
• Ignoring user action simulation in tests