Implications of Flaky Tests

Oct 13, 2025 by wbrum.org 55 views

Introduction

Flaky tests are a common issue in software development, particularly in game development, where the complexity of the game world and its interactions can lead to unpredictable test results. In this article, we will delve into the issue of flaky tests, specifically the "orphaned_genturf" test, and explore the reasons behind its flakiness. We will also discuss the implications of flaky tests and provide guidance on how to identify and fix them.

What are Flaky Tests?

Flaky tests are tests that fail intermittently, often due to external factors such as network connectivity, system resources, or concurrent access. These tests may pass on one run but fail on another, making it challenging to determine whether the test is truly failing or if it's just a fluke. Flaky tests can be caused by a variety of factors, including:

Concurrency issues: When multiple tests or processes access shared resources simultaneously, it can lead to flaky test results.
External dependencies: Tests that rely on external services or APIs may fail due to issues with those services.
System resources: Insufficient system resources, such as memory or CPU, can cause tests to fail intermittently.
Code complexity: Complex codebases can lead to flaky tests due to the increased likelihood of unexpected behavior.

The Orphaned Genturf Test

The "orphaned_genturf" test is a specific example of a flaky test. The test fails with the following message:

orphaned_genturf: Floating genturf (/turf/open/genturf) detected at (133, 125, 3) : /area/ruin/powered/beach. Why was it not replaced? at code/modules/unit_tests/orphaned_genturf.dm:7

This test is failing because it's detecting a "floating genturf" in the game world, which is not being replaced as expected. The test is failing intermittently, making it challenging to determine whether the issue is with the test itself or with the game code.

Why is the Test Flaky?

There are several reasons why the "orphaned_genturf" test is flaky:

Concurrency issues: The test may be accessing shared resources simultaneously, leading to flaky test results.
External dependencies: The test may be relying on external services or APIs that are causing the test to fail intermittently.
System resources: The test may be consuming too many system resources, leading to flaky test results.
Code complexity: The game code may be too complex, leading to unexpected behavior and flaky test results.

Implications of Flaky Tests

Flaky tests can have significant implications for game development:

Delayed development: Flaky tests can slow down development, as developers may need to spend more time debugging and fixing flaky tests.
Increased testing time: Flaky tests can increase testing time, as developers may need to run tests multiple times to ensure that the issue is not just a fluke.
Reduced confidence: Flaky tests can reduce confidence in the game's stability and performance, leading to decreased player satisfaction.

Identifying and Fixing Flaky Tests

To identify and fix flaky tests, follow these steps:

Reproduce the issue: Try to reproduce the flaky test issue to understand the root cause.
Analyze the test: Analyze the test code to identify potential issues, such as concurrency problems or external dependencies.
Isolate the issue: Isolate the issue by running the test in isolation, without any external dependencies or concurrent access.
Fix the issue: Fix the issue by addressing the root cause, such as updating dependencies or optimizing system resources.
Verify the fix: Verify the fix by running the test multiple times to ensure that the issue is resolved.

Conclusion

Flaky tests are a common issue in game development, and the "orphaned_genturf" test is a specific example of a flaky test. By understanding the reasons behind flaky tests and following the steps to identify and fix them, developers can improve the stability and performance of their game. Remember, flaky tests can have significant implications for game development, so it's essential to address them promptly and effectively.

Recommendations

To avoid flaky tests, follow these recommendations:

Write robust tests: Write tests that are robust and reliable, with minimal dependencies and concurrency issues.
Use testing frameworks: Use testing frameworks that provide features such as test isolation and dependency injection.
Monitor test performance: Monitor test performance to identify potential issues and optimize system resources.
Continuously integrate: Continuously integrate tests into the development process to catch issues early and often.

Introduction

In our previous article, we explored the issue of flaky tests, specifically the "orphaned_genturf" test, and discussed the reasons behind its flakiness. In this article, we will provide a Q&A section to address common questions and concerns related to flaky tests.

Q: What are flaky tests?

A: Flaky tests are tests that fail intermittently, often due to external factors such as network connectivity, system resources, or concurrent access. These tests may pass on one run but fail on another, making it challenging to determine whether the test is truly failing or if it's just a fluke.

Q: Why are flaky tests a problem?

A: Flaky tests can have significant implications for game development, including delayed development, increased testing time, and reduced confidence in the game's stability and performance.

Q: How can I identify flaky tests?

A: To identify flaky tests, follow these steps:

Reproduce the issue: Try to reproduce the flaky test issue to understand the root cause.
Analyze the test: Analyze the test code to identify potential issues, such as concurrency problems or external dependencies.
Isolate the issue: Isolate the issue by running the test in isolation, without any external dependencies or concurrent access.
Fix the issue: Fix the issue by addressing the root cause, such as updating dependencies or optimizing system resources.
Verify the fix: Verify the fix by running the test multiple times to ensure that the issue is resolved.

Q: How can I fix flaky tests?

A: To fix flaky tests, follow these steps:

Update dependencies: Update dependencies to the latest versions to ensure that they are stable and reliable.
Optimize system resources: Optimize system resources, such as memory and CPU, to ensure that the test can run smoothly.
Use testing frameworks: Use testing frameworks that provide features such as test isolation and dependency injection.
Monitor test performance: Monitor test performance to identify potential issues and optimize system resources.
Continuously integrate: Continuously integrate tests into the development process to catch issues early and often.

Q: How can I prevent flaky tests?

A: To prevent flaky tests, follow these best practices:

Write robust tests: Write tests that are robust and reliable, with minimal dependencies and concurrency issues.
Use testing frameworks: Use testing frameworks that provide features such as test isolation and dependency injection.
Monitor test performance: Monitor test performance to identify potential issues and optimize system resources.
Continuously integrate: Continuously integrate tests into the development process to catch issues early and often.
Test in isolation: Test in isolation to ensure that the test is not affected by external factors.

Q: What are some common causes of flaky tests?

A: Some common causes of flaky tests include:

Concurrency issues: When multiple tests or processes access shared resources simultaneously, it can lead to flaky test results.
External dependencies: Tests that rely on external services or APIs may fail due to issues with those services.
System resources: Insufficient system resources, such as memory or CPU, can cause tests to fail intermittently.
Code complexity: Complex codebases can lead to flaky tests due to the increased likelihood of unexpected behavior.

Q: How can I ensure that my tests are reliable?

A: To ensure that your tests are reliable, follow these best practices:

Write robust tests: Write tests that are robust and reliable, with minimal dependencies and concurrency issues.
Use testing frameworks: Use testing frameworks that provide features such as test isolation and dependency injection.
Monitor test performance: Monitor test performance to identify potential issues and optimize system resources.
Continuously integrate: Continuously integrate tests into the development process to catch issues early and often.
Test in isolation: Test in isolation to ensure that the test is not affected by external factors.

Conclusion

Flaky tests can have significant implications for game development, including delayed development, increased testing time, and reduced confidence in the game's stability and performance. By understanding the reasons behind flaky tests and following the steps to identify and fix them, developers can improve the stability and performance of their game. Remember, flaky tests can be prevented by following best practices and using testing frameworks that provide features such as test isolation and dependency injection.