insta-snapshots

Original：🇺🇸 English

Translated

Guide for working with and updating insta snapshot tests in Oxc without terminal interaction.

5installs

Sourceoxc-project/oxc

Added on2026-04-18

NPX Install

npx skill4agent add oxc-project/oxc insta-snapshots

SKILL.md Content

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This skill guides you through working with insta snapshot tests in the Oxc codebase without requiring terminal interaction.

What are Insta Snapshots?

Insta is a snapshot testing library for Rust. Oxc uses it extensively for:

Linter rule tests (
```
crates/oxc_linter/src/snapshots/
```
)

Semantic analysis tests (

crates/oxc_semantic/tests/integration/snapshots/

)

Other crate-specific snapshot tests

Snapshots track expected test outputs (often failures or errors). When code changes, new snapshots are generated as

.snap.new

files for review.

Running Tests and Generating Snapshots

Run tests for a specific crate:

bash

cargo test -p <crate_name>

This generates

.snap.new

files if test outputs have changed.

Reviewing Snapshots Non-Interactively

IMPORTANT: Avoid using

cargo insta review

(the interactive terminal UI). Instead, follow these steps:

1. List all pending snapshots

bash

cargo insta pending-snapshots
# Or for workspace-wide:
cargo insta pending-snapshots --workspace

This shows all

.snap.new

files waiting for review.

2. Read the snapshot files directly

New snapshots are stored as

.snap.new

files next to their corresponding

.snap

files. You can use

cargo insta pending-snapshots

to view the changes to the snapshot files.

3. Accept or reject changes

Accept all pending snapshots:

bash

cargo insta accept
# Or workspace-wide:
cargo insta accept --workspace

Accept specific snapshot(s):

bash

cargo insta accept --snapshot <snapshot_name>

Reject all pending snapshots:

bash

cargo insta reject
# Or workspace-wide:
cargo insta reject --workspace

This deletes all

.snap.new

files.

4. Verify the changes

After accepting, the

.snap.new

files become

.snap

files. Check with git:

bash

git diff <path/to/snapshots/>

Common Workflows

After fixing a bug or adding new snapshot tests:

Run tests:
```
cargo test -p oxc_linter
```
(or relevant crate)
Check pending:
```
cargo insta pending-snapshots
```
Read new snapshots to verify they match expected behavior
Accept if correct:
```
cargo insta accept
```
Commit the updated
```
.snap
```
files

Working with specific test files:

Run:

cargo test -p oxc_linter specific_test_name

Read:

cargo insta pending-snapshots

- look for

specific_test_name.snap.new

Accept:
```
cargo insta accept -p oxc_linter
```

Snapshot File Formats

```
.snap
```
- Current expected output
```
.snap.new
```
- New output from recent test run (pending review), do not commit if these files are present

Note that

.snap.md

files are from Vitest, and not Insta. They are used in conformance tests, and are not handled by the instructions in this skill.

Tips

Always review snapshots manually before accepting - don't blindly accept all changes
Snapshot files are checked into git - they're part of the test suite
Large snapshot changes may indicate breaking changes or bugs
Use
```
git diff
```
after accepting to see what actually changed
Use the CLI commands. DO NOT just copy-paste or manually edit
```
.snap
```
files.

Example: Complete Workflow

bash

# 1. Make a code change to a linter rule
# 2. Run tests
cargo test -p oxc_linter

# 3. See what changed
cargo insta pending-snapshots

# 4. Review specific snapshot (using Read tool)
# Read: crates/oxc_linter/src/snapshots/some_test.snap.new

# 5. Accept if correct
cargo insta accept -p oxc_linter

# 6. Verify with git
git diff crates/oxc_linter/src/snapshots/

# 7. Run tests again to ensure everything passes
cargo test -p oxc_linter

When to use this skill: When tests fail due to snapshot mismatches or after changing code that affects test outputs.

insta-snapshots

NPX Install

Tags

SKILL.md Content

What are Insta Snapshots?

Running Tests and Generating Snapshots

Run tests for a specific crate:

Reviewing Snapshots Non-Interactively

1. List all pending snapshots

2. Read the snapshot files directly

3. Accept or reject changes

4. Verify the changes

Common Workflows

After fixing a bug or adding new snapshot tests:

Working with specific test files:

Snapshot File Formats

Tips

Example: Complete Workflow