Measure website response time under load

Preconditions (2)

Step 1: Open the performance testing tool

Step 2: Create a test plan with 50 virtual users

Step 3: Set the test to send requests to the website homepage URL

Step 4: Run the test for 5 minutes

Step 5: Monitor the response times and error rates during the test

✅ Expected Result: The average response time should be under 2 seconds and error rate should be 0%

Automation Requirements - Apache JMeter

Assertions Needed:

Verify average response time is less than 2000 milliseconds

Verify error rate is zero

Best Practices:

Use realistic number of virtual users to simulate load

Add assertions to check response time and error rate

Use timers to simulate real user think time

Run tests for sufficient duration to get stable results

Automated Solution

Testing Fundamentals

import org.apache.jmeter.config.Arguments;
import org.apache.jmeter.engine.StandardJMeterEngine;
import org.apache.jmeter.protocol.http.control.HeaderManager;
import org.apache.jmeter.protocol.http.control.gui.HttpTestSampleGui;
import org.apache.jmeter.protocol.http.sampler.HTTPSamplerProxy;
import org.apache.jmeter.reporters.ResultCollector;
import org.apache.jmeter.samplers.SampleSaveConfiguration;
import org.apache.jmeter.testelement.TestPlan;
import org.apache.jmeter.threads.ThreadGroup;
import org.apache.jmeter.threads.gui.ThreadGroupGui;
import org.apache.jmeter.util.JMeterUtils;
import org.apache.jorphan.collections.HashTree;

public class PerformanceTest {
    public static void main(String[] args) throws Exception {
        // Set JMeter home for JMeterUtils
        String jmeterHome = System.getenv("JMETER_HOME");
        JMeterUtils.setJMeterHome(jmeterHome);
        JMeterUtils.loadJMeterProperties(jmeterHome + "/bin/jmeter.properties");
        JMeterUtils.initLocale();

        StandardJMeterEngine jmeter = new StandardJMeterEngine();

        // Create Test Plan
        TestPlan testPlan = new TestPlan("Performance Test Plan");

        // Create HTTP Sampler
        HTTPSamplerProxy httpSampler = new HTTPSamplerProxy();
        httpSampler.setDomain("example.com");
        httpSampler.setPort(80);
        httpSampler.setPath("/");
        httpSampler.setMethod("GET");
        httpSampler.setName("Homepage Request");
        httpSampler.setProperty(TestElement.TEST_CLASS, HTTPSamplerProxy.class.getName());
        httpSampler.setProperty(TestElement.GUI_CLASS, HttpTestSampleGui.class.getName());

        // Create Thread Group
        ThreadGroup threadGroup = new ThreadGroup();
        threadGroup.setName("Load Test Users");
        threadGroup.setNumThreads(50);
        threadGroup.setRampUp(10);
        threadGroup.setDuration(300); // 5 minutes
        threadGroup.setScheduler(true);
        threadGroup.setProperty(TestElement.TEST_CLASS, ThreadGroup.class.getName());
        threadGroup.setProperty(TestElement.GUI_CLASS, ThreadGroupGui.class.getName());

        // Create Test Plan tree
        HashTree testPlanTree = new HashTree();
        HashTree threadGroupHashTree = testPlanTree.add(testPlan, threadGroup);
        threadGroupHashTree.add(httpSampler);

        // Add Result Collector
        SampleSaveConfiguration saveConfig = new SampleSaveConfiguration();
        saveConfig.setTime(true);
        saveConfig.setLatency(true);
        saveConfig.setSuccess(true);
        saveConfig.setResponseCode(true);
        saveConfig.setResponseMessage(true);
        saveConfig.setThreadName(true);
        saveConfig.setDataType(true);
        saveConfig.setEncoding(true);
        saveConfig.setAssertions(true);
        saveConfig.setSubresults(true);
        saveConfig.setResponseData(false);
        saveConfig.setSamplerData(false);
        saveConfig.setAsXml(false);

        ResultCollector logger = new ResultCollector(saveConfig);
        logger.setFilename("performance_test_results.jtl");
        testPlanTree.add(testPlanTree.getArray()[0], logger);

        // Run Test Plan
        jmeter.configure(testPlanTree);
        jmeter.run();

        // After test, parse results file to assert average response time and error rate
        // (Parsing and assertions would be done in a separate step or tool)
    }
}

This code sets up a JMeter test plan programmatically.

First, it configures JMeter environment and loads properties.

Then it creates a test plan with a thread group of 50 users ramping up over 10 seconds and running for 5 minutes.

An HTTP sampler sends GET requests to the homepage of example.com.

A result collector saves test results to a file.

The test plan tree is built and the test is run.

Assertions on average response time and error rate should be done by analyzing the saved results file after the test run.

Common Mistakes - 4 Pitfalls

Using too few virtual users that do not simulate real load

Not adding assertions to check response time and errors

Running tests for too short a time

Hardcoding URLs without using variables

Bonus Challenge

Now add data-driven testing with 3 different URLs to test homepage, login page, and search page

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