In 2026, R developers use Atlas to transform overwhelming `testthat` output into a clear, prioritized list of distinct root causes, streamlining the debugging process. Atlas integrates directly with your R development environment, understanding `DESCRIPTION`-based packages and `renv` for dependency management. By leveraging Atlas's `bash` tool to run `devtools::test()`, `grep` to identify unique failure patterns, and `todowrite` to track fixes, you can systematically address issues, ensuring your R code remains robust and reliable. This approach moves beyond simply re-running tests, focusing on efficient root cause analysis and resolution.
How to run R testthat suites with Atlas and capture full output?
Running a comprehensive `testthat` suite in R can produce extensive output, often exceeding terminal buffer limits. In 2026, Atlas's `bash` tool executes `devtools::test()` with a generous timeout, ensuring even slow R packages complete their runs. It then captures the entire log, truncating the terminal display at 2000 lines but saving the full 50 KB output to a retained file for complete analysis.
When working within an R package that contains a `DESCRIPTION` file and `tests/testthat/` directory, Atlas provides a robust way to execute your test suite. Instead of manually invoking `devtools::test()` and risking truncated output, you can use `atlas bash` to manage the execution and capture. For example, to run all `testthat` tests in your R project, you would issue `atlas bash "Rscript -e 'devtools::test()'" --timeout 300000`. This command tells Atlas to run the R script that executes `devtools::test()`, providing a 300,000 millisecond (5-minute) timeout to accommodate complex or lengthy test runs. If the output exceeds Atlas's display limits, it will indicate that the output was truncated and provide the exact path to the complete log file, such as `/tmp/atlas_log_12345.txt`. This ensures that no critical failure details are lost, allowing for thorough post-run analysis.
How to group R test failures by root cause using Atlas grep?
After running an R `testthat` suite, the raw output can be a daunting wall of red text. Atlas's `grep` tool, in 2026, is essential for transforming this into actionable insights. It allows R developers to group failures by distinct root causes, rather than just by test name, by searching the complete log file for specific error patterns.
Once Atlas has captured the full `testthat` log, the next step is to identify and group distinct failure causes. Simply looking at individual test failures can be misleading, as multiple tests might fail due to a single underlying issue, such as an incorrect data type conversion or a missing dependency managed by `renv`. To achieve this, you would use `atlas grep` on the full log file. For instance, if the truncated output indicated the log was saved to `/tmp/atlas_log_12345.txt`, you might run `atlas grep "Error in|Failure in" /tmp/atlas_log_12345.txt`. This command searches for common `testthat` error indicators. More sophisticated `grep` patterns can be developed to pinpoint specific types of R errors, like `atlas grep "object '.*' not found" /tmp/atlas_log_12345.txt` to identify issues related to undefined variables or functions. This process helps consolidate redundant failures, revealing the true, distinct root causes that need attention.
How to track R test fixes with Atlas todowrite?
Tracking distinct R test failures is crucial for efficient resolution, preventing issues from being forgotten or re-introduced. In 2026, Atlas's `todowrite` tool allows R developers to create a prioritized list of pending fixes directly from the identified root causes. This ensures that each unique problem, whether in a `dplyr` pipeline or a `roxygen2` docblock, is systematically addressed.
After grouping `testthat` failures by their distinct root causes using `grep`, the next logical step is to create a structured plan for fixing them. Atlas's `todowrite` tool is designed precisely for this purpose. For each unique root cause identified in the R test log, you can create a `todowrite` entry with a `pending` status. For example, if `grep` revealed a recurring 'object not found' error originating from a specific helper function in `R/utils.R`, you would create an entry like: `atlas todowrite "Fix 'object not found' in R/utils.R affecting multiple tests" --status pending`. This creates a clear, trackable task. If another distinct cause was a `purrr` pipeline failing due to an unexpected list structure, you might add: `atlas todowrite "Adjust purrr pipeline in R/data_processing.R for list structure mismatch" --status pending`. This approach ensures that every identified root cause is recorded and tracked until resolution, preventing 'fix one, break another' scenarios and providing a clear roadmap for improving your R package's stability.
How does Atlas ensure safe R code changes and review?
Atlas prioritizes safety and transparency in R code modifications, a critical feature for any developer in 2026. Before any changes are written to your `DESCRIPTION`-based package, Atlas drafts a plan in a read-only agent, seeks explicit permission, and presents a unified diff for approval. This robust review process applies to all edits, from `testthat` fixes to `Air` formatting.
Atlas employs a multi-layered safety mechanism to ensure that all proposed changes to your R codebase are thoroughly reviewed and approved. When you use `atlas edit` to modify files like `R/my_function.R` or `tests/testthat/test_my_feature.R` to address a `testthat` failure, Atlas first operates within a read-only 'plan agent'. This agent formulates a strategy for the edit without altering any files. Before any actual modifications occur, Atlas switches to a 'build agent' and presents a permission prompt, asking for your explicit consent to proceed. Crucially, for every file edit, Atlas computes a unified diff, clearly showing exactly what changes will be made. This diff is surfaced for your approval, allowing you to inspect every line modification before it's written to disk. Furthermore, Atlas snapshots file changes as git patches, providing an additional layer of rollback capability. This comprehensive review process extends to all automated actions, including having Atlas format changed files with `Air` or regenerate `NAMESPACE` with `roxygen2`, ensuring you maintain full control over your R project's integrity.
Step by step
- 01Run your R `testthat` suite using Atlas's `bash` tool, ensuring full output capture: `atlas bash "Rscript -e 'devtools::test()'" --timeout 300000`.
- 02If the terminal output was truncated, use `atlas read` to view the complete `testthat` log file, whose path is provided in the truncation header (e.g., `/tmp/atlas_log_12345.txt`).
- 03Group distinct `testthat` failures by root cause using `atlas grep` on the full log file, rather than just by test name. For example: `atlas grep "Error in|Failure in" /tmp/atlas_log_12345.txt`.
- 04For each distinct root cause identified, create a trackable task using `atlas todowrite`. For instance: `atlas todowrite "Fix data type mismatch in R/data_prep.R affecting testthat suite" --status pending`.
- 05Select one `todowrite` entry and use `atlas edit` to modify the relevant R source file (e.g., `R/data_prep.R`) or `tests/testthat/test_feature.R` to implement the fix.
- 06After making changes, re-run only the affected `testthat` tests via `atlas bash` to quickly verify the fix without running the entire suite again. For example: `atlas bash "Rscript -e 'devtools::test(filter = "data_prep")'" --timeout 60000`.
- 07Approve Atlas's proposed changes, reviewing the unified diff, and then mark the `todowrite` entry as complete once the R test passes and the code is formatted with `Air`.
Frequently asked questions
- How does Atlas handle large `testthat` output in R?
- Atlas's `bash` tool executes `devtools::test()` and captures the complete output, even if it exceeds terminal display limits. It truncates the terminal view at 2000 lines or 50 KB but writes the full log to a retained file, providing you with the path for comprehensive review using `atlas read`.
- Can Atlas help me find the root cause of multiple R `testthat` failures?
- Yes, Atlas helps you move beyond individual test failures. After running your `testthat` suite, you can use `atlas grep` on the complete log file to identify recurring error patterns and group failures by their distinct root causes, making triage much more efficient for your R project.
- How does Atlas ensure my R code changes are safe?
- Atlas employs a robust safety protocol. It drafts plans in a read-only agent, asks for explicit permission before executing, and presents a unified diff for every file edit. You must approve these changes before they are written to your R files, and Atlas also creates git patch snapshots for easy rollback.
- Does Atlas integrate with R's package management like `renv`?
- Yes, Atlas is designed to work direct within R environments that use `DESCRIPTION`-based packages and `renv` for dependency locking. Atlas can read your `renv.lock` file and understand your package structure, ensuring its operations are context-aware within your R project.
- Can Atlas help me format my R code after fixing tests?
- Absolutely. After you've made changes to fix `testthat` failures, Atlas can be instructed to format the modified R files using `Air`. This action, like all others, will be permission-gated, and Atlas will present a diff of the formatting changes for your approval before writing them.
- How do I track specific R test fixes with Atlas?
- Atlas's `todowrite` tool is perfect for this. Once you've identified a distinct root cause for a `testthat` failure in your R code, you can create a `todowrite` entry with a `pending` status. This allows you to track the fix through its lifecycle, ensuring no issue is overlooked.
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