bun-match-svg

A custom matcher for Bun tests to compare SVG snapshots.

Quick Start

The fastest way to get started is to use the CLI to initialize your project:

bunx bun-match-svg init

This will:

1. Create an example test in tests/svg.test.ts
2. Set up automatic preloading by creating:
   • tests/fixtures/preload.ts
   • bunfig.toml

You can then run the example test:

bun test

Installation

bun add -D bun-match-svg

Usage

Basic Usage

Import the library in your test file:

import "bun-match-svg"

test("your SVG test", () => {
  const svgContent = generateSomeSvg() // Your function to generate SVG
  expect(svgContent).toMatchSvgSnapshot(import.meta.path, "uniqueName")
})

The toMatchSvgSnapshot matcher takes two arguments:

1. import.meta.path: The path of the current test file.
2. uniqueName (optional): A unique name for the snapshot. If not provided, it will use the test file name.

Automatically Preload

To make toMatchSvgSnapshot available in all your test files without importing it in each one:

1. Create a file tests/fixtures/preload.ts with the following content:

import "bun-match-svg"

2. Define a bunfig.toml file in your project root with:

[test]
preload = ["./tests/fixtures/preload.ts"]

Now toMatchSvgSnapshot will be automatically available in every test file.

How It Works

• On first run, it creates a snapshot of your SVG.
• On subsequent runs, it compares the current SVG with the snapshot.
• If differences are found, it generates a diff image.

Updating Snapshots

To update existing snapshots, run your tests with:

bun test --update-snapshots

Or set the environment variable:

BUN_UPDATE_SNAPSHOTS=1 bun test

Configuration

The matcher uses looks-same for comparison with these default settings:

• strict: false
• tolerance: 2

There currently isn't a way to configure this, but PRs welcome!

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

License

This project is open source and available under the MIT License.