JMeter Tutorial on Performance Testing

Introduction to JMeter

• JMeter: An open-source, Java-based application for performance testing.
• Initially designed for web applications, now supports API performance testing too.

Importance of Performance Testing

• Ensures smooth user experience.
• Prevents application slowdown or crash during high traffic, which can impact revenue.
• Essential for applications expecting high traffic, such as e-commerce platforms.

Setting Up JMeter on Windows

1. Download and Install Java
   • Needed because JMeter is a Java application.
   • Set environment variables for Java.
2. Download JMeter
   • Verify Java installation.
   • Download JMeter from the official website.
   • Extract and run the JMeter batch file.

JMeter Directory Structure

• Root Folder: Apache-JMeter-<version>
• Subfolders explained:
  • bin: Scripts to run JMeter, examples, templates.
  • lib: Libraries and extensions.
  • docs: Technical documentation.
  • extras: Files for building JMeter.
  • printable_docs: Printable documentation and user manuals.
• Backups for script recovery.

JMeter User Interface Overview

• Test Plan: Area to create test scripts.
• Thread Groups: Define number of virtual users.
• Samplers: Types of requests to the server.
• Listeners: Analyze performance metrics and logs.
• Menu Bar Options: File, Edit, Run, Options, Tools, Help.
  • Best Practice: Use command line (CLI) mode for load testing.
• Tool Bar Shortcuts for quick actions.
• Thread Properties: Configure number of threads, ramp-up period, and loop count.

JMeter Elements

• Test Elements:
  • Thread Groups: Number of users/threads.
  • Samplers: Types of requests (HTTP, FTP, JDBC, etc.).
  • Listeners: View test results and logs.
  • Config Elements: Configuration settings for requests.
  • Timers: Add delays between requests.
  • Pre-processors and Post-processors: Modify request data.
  • Assertions: Validate response data.
  • Logic Controllers: Control the flow of test script execution.
• Non-test Elements: Help create test scripts (e.g., HTTP Test Script Recorder).

Creating a JMeter Script

• Example: E-commerce promotion load test.
  • Create Thread Group, Add Sampler, Add Listener.
  • Define user flow and validate responses.
  • Use assertions to validate response data.

Assertions in JMeter

• Purpose: Verification of response data or performance metrics.
• Types: Response Assertions, Duration Assertions, Size Assertions, etc.
• Usage: Configure fields to test, pattern matching rules, and expected outcomes.
• Listener: Assertion Results for detailed assertion logs.

Using Plugins in JMeter

• Plugins Manager: Install, manage, and update plugins.
• Popular Plugins: Extensions to enhance JMeter functionality.
• Installation: Download plugin manager JAR, add to /lib/ext directory, restart JMeter.
• Configuration: Customize plugin settings via GUI.

Database Performance Testing with JMeter

• JDBC Connection Configuration: Set up connection to the database.
• JDBC Request: Execute SQL queries and validate results.
• Example: Test query performance with multiple users.

API Testing with JMeter

• SOAP and REST API Testing:
  • SOAP: Use HTTP Sampler, specify XML body.
  • REST: HTTP Sampler, specify query parameters and JSON body.
  • Validate API responses and measure performance.

FTP Testing with JMeter

• FTP Sampler: Upload and download files.
• Configuration: Set up server connection and choose file transfer operations.
• Performance Testing: Measure upload/download times with multiple users.

Running JMeter Scripts from Command Line (CLI)

• Benefits: Saves memory and system resources, suitable for continuous integration (CI).
• Command Syntax: jmeter -n -t test_plan.jmx -l result_file.csv -e -o /path/to/output/folder
• Handling Errors: Verify paths, ensure result files are empty before execution.

Generating HTML Reports in JMeter

• Methods:
  • Command Line with new results: -e -o directory flag.
  • Command Line with existing results: Use -g option with result file and output directory.
  • GUI: Tools > Generate HTML Report.
• Customizing Reports: Edit user.properties, update thresholds and titles.

Making JMeter Scripts Data-Driven

• CSV Data Set Config: Load data from CSV files.
• Parameterization: Replace hardcoded values with CSV variables.
• Example: Dynamic user data for API tests.

Timers in JMeter

• Purpose: Simulate real user think-time between requests.
• Types: Constant Timer, Uniform Random Timer, etc.
• Configuration: Add timers at test plan, thread group, or request level.

Variables and Functions in JMeter

• Variables: Store values to make scripts modular and easy to update.
• Functions: Predefined methods to generate data (e.g., random strings, dates).
• Helper Dialog: Tool to generate and test functions within JMeter.

Logic Controllers in JMeter

• Simple Controller: Organize test plans without affecting execution.
• Once Only Controller: Execute requests only once per thread, regardless of loop count.
• Loop Controller: Execute requests multiple times within specified loops.
• Interleave Controller: Alternates execution between nested requests.

HTML Link Parser in JMeter

• Pre-Processor: Parses HTML response and extracts URLs or forms.
• Use Cases: Spidering (random link clicking), handling dynamic data.
• Example: Randomly navigate through web pages using parsed links.