Writes Java TestNG classes with @Test groups, @DataProvider, testng.xml suites, parallel thread-count, ITestListener, and SoftAssert. Trigger on TestNG, Surefire suite XML, or dependsOnMethods. Not for pytest/conftest (pytest-skill) or JUnit-only trees.
Install with Codex or Claude Copy this prompt, paste it into Codex, Claude, or another assistant, and let it review the skill page and install it for you.
A direct command skips the review prompt. Inspect the source before running it.
Writes Java TestNG classes with @Test groups, @DataProvider, testng.xml suites, parallel thread-count, ITestListener, and SoftAssert. Trigger on TestNG, Surefire suite XML, or dependsOnMethods. Not for pytest/conftest (pytest-skill) or JUnit-only trees.
This skill provides production-grade TestNG test generation patterns for Java projects. It covers groups, data providers, parallel execution, XML suite configuration, listeners, soft assertions, and lifecycle annotations. Use the core patterns below for everyday work; load the deep playbook reference when the task requires advanced configuration such as thread-safe drivers, factories, CI/CD integration, or reporting frameworks.
When to Use
Use this skill when the user needs to generate or configure TestNG tests in Java. Trigger keywords and phrases:
"TestNG"
"@DataProvider"
"testng.xml"
"TestNG suite"
"parallel tests Java"
"groups" (in a Java testing context)
"@Listeners", "ITestListener"
"SoftAssert"
"dependsOnMethods"
"Surefire TestNG"
Do not use this skill for JUnit-only projects. If the user mentions JUnit without TestNG, defer to a JUnit skill.
<suiteparallel="methods"thread-count="5"><!-- Method level --><suiteparallel="classes"thread-count="5"><!-- Class level --><suiteparallel="tests"thread-count="5"><!-- Test level -->
For thread-safe driver patterns (ThreadLocal, ConfigReader), load references/playbook.md §3.
6. Use soft assertions for multi-check scenarios
SoftAssertsoft=newSoftAssert();
soft.assertEquals(user.getName(), "Alice");
soft.assertEquals(user.getAge(), 25);
soft.assertTrue(user.isActive());
soft.assertAll(); // Reports all failures at once
For production listener suites (retry analyzers, screenshot capture, timing), load references/playbook.md §6.
8. Run the tests
Task
Command (PowerShell)
Run suite
mvn test -DsuiteXmlFile=testng.xml
Run group
mvn test -Dgroups=smoke
Run single class
mvn test -Dtest=LoginTest
Run single method
mvn test -Dtest=LoginTest#testLoginSuccess
9. Check reports
Default TestNG HTML report:
test-output\index.html
Open in a browser:
Start-Process test-output\index.html
For Allure or ExtentReports integration, load references/playbook.md §10.
Pitfalls
Hard rules — do not violate
Never use dependsOnMethods everywhere. Cascading failures make debugging impossible. Prefer independent tests; use dependsOnGroups sparingly for true ordering dependencies.
Never omit groups. Without @Test(groups = "...") you cannot run subsets via -Dgroups. Always assign at least one group.
Never hard-code test data inside test methods when a data provider is appropriate. Use @DataProvider for reusable, maintainable data sets.
Never rely on priority ordering as a substitute for independent tests. Priority-based ordering is fragile and breaks when tests are added or removed.
Never assume thread safety in parallel mode. When parallel="methods" or higher, shared state (e.g., a static WebDriver) will cause race conditions. Use ThreadLocal per-thread drivers.
Never mix line endings in testng.xml on Windows. Ensure consistent LF or CRLF; mixed endings can cause Surefire XML parsing failures.
Anti-patterns quick reference
Bad
Good
Why
dependsOnMethods everywhere
Independent tests
Cascading failures
No groups
@Test(groups = "smoke")
Can't run subsets
Hard-coded test data
@DataProvider
Reusable
Priority ordering
Independent tests
Fragile
Shared static driver in parallel
ThreadLocal<WebDriver>
Race conditions
Assert after every check in long method
SoftAssert.assertAll() at end
Only first failure reported
Common debugging problems
For the full 12-problem debugging quick-reference, load references/playbook.md §12.
Verification
After generating or modifying TestNG tests, verify with these checkable steps:
Compile the project:
mvn compile test-compile
Expected: BUILD SUCCESS
Run the suite and confirm tests execute:
mvn test -DsuiteXmlFile=testng.xml
Expected: BUILD SUCCESS with Tests run: N, Failures: 0, Errors: 0, Skipped: 0
Run a specific group to confirm group filtering works:
mvn test -Dgroups=smoke
Expected: only tests annotated @Test(groups = "smoke") execute.
Verify the HTML report was generated:
Test-Path test-output\index.html
Expected: True
Verify parallel execution by checking thread count in logs — TestNG logs thread pool usage when parallel is set. Confirm thread-count matches the suite XML value.
Verify data provider invocation count — a test using @DataProvider with 3 data rows should show Tests run: 3 for that single method.
References
The following reference file contains deep patterns beyond the core skill:
File
When to Load
references/playbook.md
When the task requires advanced configuration: Maven/Surefire setup, multi-env suite XML, ThreadLocal drivers, Excel/JSON/CSV data providers, @Factory cross-browser matrix, production listeners (retry, screenshot, timing), Page Object integration, mixed parallel strategies, Allure/ExtentReports, CI/CD (GitHub Actions, Jenkins), or the 12-problem debugging guide.
Playbook section index
§
Section
Focus
1
Project Setup & Configuration
Maven + Surefire config
2
Suite XML Configuration
Multi-env, parallel, groups
3
BaseTest & Thread-Safe Driver
ThreadLocal, ConfigReader
4
Data Providers (Advanced)
Excel, JSON, CSV, parallel, cross-class
5
Factory Pattern
Cross-browser matrix
6
Listeners (Production Suite)
Retry, screenshot, timing
7
Soft Assertions & Dependencies
Groups, method deps
8
Page Object Integration
PageFactory, fluent POs
9
Parallel Execution Strategies
Method/class/test/mixed
10
Reporting Integration
Allure, ExtentReports
11
CI/CD Integration
GitHub Actions, Jenkins
12
Debugging Quick-Reference
12 common problems
13
Best Practices Checklist
14 items
Limitations
Use this skill only when the task clearly matches TestNG testing in Java and the local project context supports it.
Verify commands, generated code, dependencies, credentials, and external service behavior before applying changes.
Do not treat examples as a substitute for environment-specific tests, security review, or user approval for destructive or costly actions.
This skill does not cover TestNG for Kotlin or non-JVM languages.
Related Skills
junit-skill — JUnit 5 testing patterns (use when the project uses JUnit, not TestNG).
maven-skill — Maven build lifecycle and plugin configuration (use when configuring Surefire/Failsafe beyond TestNG defaults).
selenium-skill — Selenium WebDriver patterns (use alongside this skill for browser automation tests with TestNG).
