qa-jmeter-writer

name	qa-jmeter-writer
description	Generate JMeter performance test plans in XML/JMX format with thread groups, samplers, listeners, assertions, and CI-ready configuration.
output_dir	tests/performance

QA JMeter Writer

Purpose

Write JMeter test plans (.jmx) from performance test specifications. Transform structured performance requirements (from qa-plan-creator performance plans, qa-nfr-analyst NFR specs) into executable JMeter XML test plans with thread groups, samplers, listeners, assertions, and CI-ready configuration.

Trigger Phrases

• "Write JMeter tests for [API/endpoint]"
• "Generate JMeter load tests from performance plan"
• "Create JMeter .jmx for [service]"
• "JMeter thread group with HTTP samplers"
• "JMeter test plan with assertions and listeners"
• "JMeter CSV data parameterization"
• "JMeter CI integration non-GUI mode"
• "JMeter distributed load test plan"
• "JMeter JSON assertion for API"
• "JMeter JSR223 Groovy preprocessor"

Key Features

Feature	Description
Thread Groups	Users, ramp-up, loops, duration for load modeling
HTTP Request Sampler	URL, method, body, headers, path
JDBC/JMS Samplers	Database and messaging protocol support
Listeners	Aggregate Report, Summary Report, Graph Results, View Results Tree
Assertions	Response Assertion, Duration Assertion, Size Assertion, JSON Assertion
CSV Data Set Config	Parameterization from CSV files
Extractors	Regular Expression Extractor, JSON Extractor
Timers	Constant, Uniform Random, Gaussian for think time
Pre/Post Processors	JSR223 (Groovy), BeanShell for correlation

Workflow

1. Read performance plan — From qa-plan-creator (performance plan) or qa-nfr-analyst (NFR specs)
2. Design thread groups — Map load profiles to Thread Group (users, ramp-up, loops, duration)
3. Add samplers — HTTP Request, JDBC, JMS as needed
4. Configure assertions — Response, Duration, Size, JSON for validation
5. Add listeners — Aggregate Report, Summary Report for results
6. Generate .jmx — Produce valid JMeter XML test plan file

Key Patterns

Pattern	Usage
Thread Group	num_threads, ramp_time, loops, duration for load modeling
HTTP Request	Domain, path, method, body, headers
Response Assertion	Status code, response text, response code
Duration Assertion	Max response time (ms)
JSON Assertion	JSONPath, expected value
CSV Data Set Config	Filename, variable names, delimiter
Regular Expression Extractor	Regex, template, match number, variable
JSR223 PreProcessor	Groovy script for correlation

Thread Group Example

<ThreadGroup guiclass="ThreadGroupGui" testclass="ThreadGroup" testname="Load Users" enabled="true">
  <stringProp name="ThreadGroup.num_threads">50</stringProp>
  <stringProp name="ThreadGroup.ramp_time">60</stringProp>
  <elementProp name="ThreadGroup.main_controller" elementType="LoopController">
    <stringProp name="LoopController.loops">-1</stringProp>
    <stringProp name="ThreadGroup.duration">300</stringProp>
  </elementProp>
</ThreadGroup>

HTTP Request Sampler

<HTTPSamplerProxy guiclass="HttpTestSampleGui" testclass="HTTPSamplerProxy" testname="GET /api/users" enabled="true">
  <stringProp name="HTTPSampler.domain">api.example.com</stringProp>
  <stringProp name="HTTPSampler.path">/api/users</stringProp>
  <stringProp name="HTTPSampler.method">GET</stringProp>
  <boolProp name="HTTPSampler.use_keepalive">true</boolProp>
</HTTPSamplerProxy>

Response Assertion

<ResponseAssertion guiclass="AssertionGui" testclass="ResponseAssertion" testname="Status 200" enabled="true">
  <collectionProp name="Assertion.test_strings">
    <stringProp name="49586">200</stringProp>
  </collectionProp>
  <stringProp name="Assertion.custom_message"></stringProp>
  <stringProp name="Assertion.test_field">Assertion.response_code</stringProp>
  <boolProp name="Assertion.assume_success">false</boolProp>
</ResponseAssertion>

See references/patterns.md for thread groups, samplers, assertions, extractors, timers, controllers.

Output

• JMeter test plans — .jmx files in tests/, performance/, or jmeter/ per project convention
• Run via CLI — jmeter -n -t test.jmx -l results.jtl -e -o report/
• CI integration — Non-GUI mode (-n), JTL results (-l), HTML report (-e -o)

CI Integration

Option	Description
-n	Non-GUI mode (headless)
-t test.jmx	Test plan file
-l results.jtl	Results file (JTL/CSV)
-e	Generate HTML report after run
-o report/	Output directory for HTML report
-Jprop=value	Override JMeter properties

Scope

Can do (autonomous):

• Generate .jmx test plans from performance plans and NFR specs
• Design thread groups (users, ramp-up, loops, duration)
• Add HTTP, JDBC, JMS samplers with proper configuration
• Configure Response, Duration, Size, JSON assertions
• Add CSV Data Set Config for parameterization
• Add Regular Expression Extractor, JSON Extractor for correlation
• Add timers (Constant, Uniform Random) for think time
• Add JSR223 PreProcessor (Groovy) for dynamic logic
• Add listeners (Aggregate Report, Summary Report)
• Generate CI-ready run commands

Cannot do (requires confirmation):

• Change production service configuration
• Target production without explicit consent
• Add JMeter plugins not in standard distribution
• Override project JMeter config without approval

Will not do (out of scope):

• Execute tests (user runs jmeter -n -t test.jmx)
• Write E2E functional tests (use qa-playwright-ts-writer)
• Provision load infrastructure (distributed JMeter setup)
• Modify CI/CD pipelines beyond JMeter integration

References

• references/patterns.md — Thread groups, samplers, assertions, extractors, timers, controllers
• references/config.md — CLI mode, properties, plugins, distributed testing
• references/best-practices.md — Non-GUI mode, parameterization, correlation, result analysis

Quality Checklist

• Thread groups match performance plan load profiles (users, ramp-up, duration)
• Assertions validate critical responses (status, duration, size)
• No hardcoded secrets; use ${__P()} or CSV for credentials
• Think time (timers) between requests where realistic
• Listeners suitable for CI (Aggregate Report, Summary Report; avoid View Results Tree in load runs)
• CSV Data Set Config for parameterization when needed
• Extractors for correlation when session/token required
• Test plan runs in non-GUI mode without errors

Troubleshooting

Symptom	Likely Cause	Fix
OutOfMemoryError in JMeter	Too many threads or listeners	Reduce threads; remove View Results Tree; increase JVM heap (-Xmx)
Assertions fail in CI	Different baseline or env	Align assertion thresholds; use ${__P()} for env-specific values
High error rate	Timeouts, 5xx, or wrong assertions	Increase timeout; fix assertion logic; verify endpoint
CSV not found	Relative path	Use absolute path or ${__BeanShell(import org.apache.jmeter.services.FileServer; FileServer.getFileServer().getBaseDir();)}
Correlation fails	Extractor order or regex	Ensure extractor runs before dependent sampler; verify regex
JMX invalid XML	Malformed elements	Validate XML; ensure proper closing tags; check JMeter version compatibility
Slow HTML report	Large JTL file	Use Aggregate Report listener; reduce sample logging; filter by label