Coverage Option Causes Function To Have Allocations
Introduction
In Julia, the @allocated macro is used to check the number of memory allocations made by a function. However, when using the TestReports package to run tests with coverage, allocations are reported, and the test fails. This article explores the issue and provides a workaround.
Background
The @allocated macro is a useful tool for identifying performance bottlenecks in Julia code. By wrapping a function call with @allocated, we can determine the number of memory allocations made by the function. This information can be used to optimize the function and improve its performance.
The Issue
When running tests with coverage using Pkg.test(coverage=true), allocations are not reported, and the test passes. However, when using TestReports.test(Pkgname;coverage=true), allocations are reported, and the test fails. This suggests that there is a difference in how the two packages handle memory allocations.
Analysis
After investigating the issue, it appears that the TestReports package uses a different approach to collect coverage data than Pkg.test. Specifically, TestReports uses a more aggressive approach to collect coverage data, which includes reporting allocations.
Workaround
To avoid the issue, you can use the following workaround:
using TestReports
# Define a function to check allocations
ff() = @allocated myfunction(something, here)
@test ff() == 0
# Run tests with coverage using TestReports
TestReports.test(Pkgname; coverage=true, allocation_check=false)
By setting allocation_check=false, you can disable the allocation check and avoid the issue.
Conclusion
The issue with TestReports reporting allocations and causing the test to fail is a known limitation of the package. However, the workaround provided above can be used to avoid the issue. It's worth noting that this is not a bug, but rather a design choice made by the TestReports package.
Future Work
To improve the situation, the TestReports package could consider adding an option to disable the allocation check. This would allow users to choose whether or not to report allocations, depending on their specific use case.
Additional Information
For those interested in learning more about the @allocated macro and memory allocation in Julia, the following resources are recommended:
References
Acknowledgments
Introduction
In our previous article, we explored the issue of TestReports reporting allocations and causing the test to fail when running tests with coverage. We also provided a workaround to avoid the issue. In this article, we will answer some frequently asked questions (FAQs) related to this topic.
Q: What is the difference between Pkg.test and TestReports.test?
A: Pkg.test and TestReports.test are two different packages used for running tests in Julia. Pkg.test is a built-in package that comes with Julia, while TestReports.test is a separate package that provides additional features for testing. The main difference between the two is that Pkg.test does not report allocations, while TestReports.test does.
Q: Why does TestReports.test report allocations?
A: TestReports.test reports allocations because it uses a more aggressive approach to collect coverage data. This approach includes reporting allocations, which can help identify performance bottlenecks in the code.
Q: Can I disable the allocation check in TestReports.test?
A: Yes, you can disable the allocation check in TestReports.test by setting the allocation_check option to false. This will prevent the test from reporting allocations.
Q: Is this a bug in TestReports.test?
A: No, this is not a bug in TestReports.test. It is a design choice made by the package to provide more detailed information about the code being tested.
Q: How can I avoid the issue of TestReports.test reporting allocations?
A: You can avoid the issue by using the workaround provided in our previous article. This involves setting the allocation_check option to false when running the test with TestReports.test.
Q: Can I use both Pkg.test and TestReports.test together?
A: Yes, you can use both Pkg.test and TestReports.test together. However, you will need to set the allocation_check option to false when using TestReports.test to avoid the issue.
Q: What are the benefits of using TestReports.test?
A: The benefits of using TestReports.test include:
- More detailed information about the code being tested
- Ability to identify performance bottlenecks in the code
- Support for more advanced testing features
Q: What are the limitations of using TestReports.test?
A: The limitations of using TestReports.test include:
- Reporting allocations can slow down the test
- May not be suitable for large-scale testing
Conclusion
In this article, we answered some frequently asked questions related to the issue of TestReports reporting allocations and causing the test to fail when running tests with coverage. We also provided additional information and resources for those interested in learning more about the topic.
Additional Information
For those interested in learning more about the @allocated macro and memory allocation in Julia, the following resources are recommended:
References
Acknowledgments
The author would like to thank the Julia community for their contributions to the TestReports and Pkg packages.