In 2026, Atlas helps Bun developers efficiently triage test failures by transforming extensive `bun test` output into a prioritized list of distinct root causes. Atlas leverages its `bash` tool to run the suite, `grep` to group failures, and `todowrite` to track fixes, ensuring a streamlined debugging workflow for your Bun projects.
How Atlas runs `bun test` and manages large output logs
Atlas streamlines running your `bun test` suite, even in 2026, by using its `bash` tool to execute `bun test` with a generous timeout. It automatically truncates output at 2000 lines or 50 KB in the terminal, but always writes the complete log to a retained file for full analysis.
When you instruct Atlas to run your test suite, it uses the `atlas bash` tool to execute `bun test` with a specified timeout, preventing slow suites from being prematurely terminated. Bun's test runner is known for its incredible speed, often completing suites in milliseconds, which allows Atlas to iterate on failures almost instantly. While the terminal output is intelligently truncated to prevent overwhelming your screen with a wall of red, Atlas ensures no information is lost. The full, untruncated log is always saved to a dedicated file, and Atlas provides the exact path to this file. This means you can always access the complete context of all test failures, regardless of the terminal display limits, ensuring comprehensive triage of your Bun project's test results.
Grouping `bun test` failures by root cause using Atlas `grep`
To efficiently triage `bun test` failures in 2026, Atlas helps you group them by distinct root causes rather than individual test names. This approach, powered by Atlas's `grep` tool, transforms a long list of 100s of failing tests into a manageable set of actionable issues.
After running your `bun test` suite, the raw output can be extensive, often listing many individual test failures that stem from a single underlying bug. Atlas encourages a workflow where you use its `grep` tool to analyze the complete test log, which was saved to a file, to identify common error patterns or stack traces. Instead of fixing each failing test in isolation, you focus on the core problem. For example, if 15 different tests fail due to an issue in a shared utility function, `atlas grep` helps you quickly identify that single root cause. This method significantly reduces the number of distinct issues you need to address, making the triage process for your Bun application much more efficient and targeted.
Tracking `bun test` failure fixes with Atlas `todowrite`
Once distinct root causes for `bun test` failures are identified, Atlas helps you track their resolution using its `todowrite` tool. This ensures that every identified issue, from a critical bug to a minor inconsistency, is recorded with a 'pending' status and not forgotten in your 2026 development cycle.
For each distinct root cause identified in your `bun test` output, Atlas allows you to create a `todowrite` entry. This is crucial for maintaining a clear, prioritized list of tasks. Instead of relying on memory or scattered notes, every actionable item is formally documented. Each `todowrite` entry represents a single, distinct problem that needs a fix, ensuring that your efforts are focused and measurable. As you work through the list, you can update the status of each entry, providing a transparent view of your progress in resolving the `bun test` failures. This systematic approach prevents issues from falling through the cracks and provides a structured way to manage the debugging process for your Bun project.
Iterative fixing and code review for Bun projects with Atlas
Atlas facilitates an iterative fixing process for `bun test` failures, allowing you to address one root cause at a time using its `edit` tool. After each change, you can re-run only the affected tests via `atlas bash`, ensuring rapid feedback and a focused debugging experience in 2026.
When you are ready to fix a specific root cause, Atlas's `edit` tool provides a controlled environment for making code changes. After modifying your Bun-native APIs or application logic, you do not need to re-run the entire `bun test` suite. Instead, you can use `atlas bash` to execute only the relevant test files or specific tests that were failing due to the issue you just addressed. This significantly speeds up the iteration cycle, leveraging Bun's near-instant execution times. Before committing your changes, Atlas computes a unified diff, clearly showing every modification. It can also run `bun fmt` over the diff to ensure your code adheres to formatting standards, providing a clean and consistent codebase for your Bun project. This granular control and immediate feedback loop are essential for efficient debugging.
How Atlas ensures safety and transparency in Bun development
Atlas prioritizes safety and transparency in your Bun development workflow, especially in 2026, by implementing permission-gated tool calls and a read-only plan agent. Every action, from running `bun test` to modifying a `package.json` script, requires explicit approval, giving you full control over your codebase.
Atlas operates with a strong emphasis on user control and transparency. Before any Atlas tool, such as `bash` to run `bun test` or `edit` to modify a `Bun.serve` implementation, executes a command that could alter your system or code, it prompts for your explicit permission. This permission-gated system ensures that you are always aware of and approve every action Atlas takes. Furthermore, Atlas drafts a comprehensive plan in a read-only plan agent before switching to a build agent, allowing you to review the proposed steps without any risk of unintended changes. For every file edit, Atlas computes and surfaces a unified diff for your approval, ensuring you understand precisely what changes will be written to your Bun project. Atlas also integrates with Git, allowing it to read branches, status, and diffs, and can stage and create commits on your behalf, all under your direct supervision. This robust safety framework provides confidence when working with Atlas on your critical Bun applications.
Step by step
- 01Initiate the `bun test` suite with Atlas's `bash` tool, providing a generous timeout in milliseconds to prevent premature termination: `atlas bash 'bun test --timeout 60000'`.
- 02If the terminal output was truncated, use `atlas read` to view the complete test log file path provided in the truncation header.
- 03Group the failures by distinct root cause using `atlas grep` on the saved full log, rather than focusing on individual test names.
- 04Record each distinct root cause as a `todowrite` entry with a 'pending' status, ensuring all identified issues are tracked.
- 05Select one pending `todowrite` entry and use `atlas edit` to make the necessary code changes in your Bun project.
- 06After making changes, re-run only the affected tests or specific test files using `atlas bash 'bun test <path/to/affected/test.ts>'` to quickly confirm the fix.
- 07Review the proposed changes, including a unified diff and an optional `bun fmt` pass over the diff, before approving.
- 08Approve the changes, allowing Atlas to stage and create a commit on your behalf, integrating the fix into your Bun codebase.
Frequently asked questions
- How does Atlas handle large `bun test` output?
- Atlas's `bash` tool truncates terminal output at 2000 lines or 50 KB but always writes the complete `bun test` log to a retained file. You can then use `atlas read` to access the full log for comprehensive analysis.
- Can Atlas help me find the root cause of a `bun test` failure?
- Yes, Atlas guides you to use its `grep` tool on the complete `bun test` log to identify common error patterns and group failures by distinct root causes, rather than individual test names.
- How does Atlas ensure my Bun code changes are safe?
- Atlas employs permission-gated tool calls, drafts plans in a read-only agent, and presents a unified diff for every proposed file edit. You must explicitly approve all changes before they are written to your Bun project.
- Does Atlas integrate with `bun fmt`?
- Absolutely. Atlas can run `bun fmt` over the diff of your proposed changes before you approve a commit, ensuring your Bun code adheres to your project's formatting standards automatically.
- Can Atlas work with Bun's native APIs like `Bun.serve`?
- Yes, Atlas is designed to understand and interact with Bun-native APIs such as `Bun.serve`, `Bun.file`, and `bun:sqlite`. It can even help replace Node compatibility shims with native Bun APIs.
- How does Atlas track test failures in a Bun project?
- After identifying distinct root causes from `bun test` output, Atlas uses its `todowrite` tool to create entries for each cause. This allows you to track the status of fixes and ensure no issue is forgotten.
- What if my `bun test` suite takes a long time to run?
- While Bun's test runner is exceptionally fast, Atlas's `bash` tool allows you to pass a generous timeout in milliseconds when running `bun test`. This prevents the suite from being killed mid-run, ensuring full execution even for slower tests.
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