Apache JMeter™

The Apache JMeter™ application is open source software, a 100% pure Java application designed to load test functional behavior and measure performance. It was originally designed for testing Web Applications but has since expanded to other test functions.

Configuration

Connect to a SQL Server database

We need the SQL Server JDBC driver so that we can connect to the database

Unzip the folder to a memorable directory

Under the root Test Plan node set the classpath to include the .jar file you just downloaded

Simulating users

The Thread Group node allows you specify how many users you want to test at a time. Each thread essentially acts as a single user

A Ramp-up period of 5 seconds with 5 users will create 1 thread (user) per second, while a Ramp-up period of 0 will create all 5 threads (users) instantly

Variables

Variables are a powerful feature in JMeter that can be utilized to pipe response data from one request into the request body of the next

The simplest way to capture response data into variables is to setup a JSON Extractor for your request. Right click on the request node and select Add -> Post-processors -> JSON Extractor. You specify the response property you want to save with JsonPath and the variable name to save into just above it

Variables can be interpolated into request bodies with the ${variable_name} syntax

Built-In Functions

JMeter has many built-in functions that can helpful in scripting a test. All functions are prefixed with two (2) underscores (__)

Recording a Test

Configuring the Recording Proxy

Navigate to the HTTP(S) Test Script Recorder node. Note the port number for the next step. Click Start and accept/decline any self-signed certificates that pop up

Open up the Firefox browser and navigate under Options -> Network Settings to the proxy connection settings. Select the Manual Proxy Configuration radio button, set Http Proxy to "localhost" and the Port to match JMeter's port

Recording a test

Still in Firefox, navigate to the page you would like to test and proceed through a test round. Click Stop to halt the test recording.

Under the Recording Controller node in JMeter, you should see requests to the pages you navigated to. Strip out any fluff from the captured requests (you can also add filters to the Test Script Recorder).

You now should have a functioning JMeter test script.

Debugging

To debug your test you can click the green Start icon in the navbar. Requests will be visible in the View Results Tree node after a couple of seconds.

If you need to inspect variables, right click on the Thread Group and select Add -> Sampler -> Debug Sampler. Drag the Debug Sampler to where you want the view the variables, run the Test Plan, and view the variables in the View Results Tree

Performance Testing

While debugging the test from the GUI is great, it can cause slowdowns when testing for performance. The CLI mode can be used instead:

Running a JMX File from the CLI

jmeter -n -e `
-t "test_plan.jmx" `
-l "results" `
-o "report"

The report folder contains a statically generated web page that contains a bunch of useful information on how well your feature performed