Rollup-Plugin-Create-Test-Package-Json

If you create a separate package to test your package's pack file, you'll need a package.json for it. This Rollup plugin generates that package.json file for you.

This plugin:

• Grabs the external dependencies for the unit tests as Rollup is generating them
• Uses the package versions specified in your package.json for the external dependencies
• Pulls peer dependencies from your package.json
• Merges the fields you specify in the plugin options into the generated package.json for the test
• Writes the package.json to Rollup's output.dir

This plugin is used by @toolbuilder/rollup-config-pkgtest, which builds and runs package tests in a temporary package.

Here's the context in which this plugin is suitable:

• Your unit tests are ES modules written using relative imports (e.g. ../src/some-file-from-your-module)
• You want to reuse your unit tests as package tests, with your package as an external dependency
• You can use Rollup to convert unit tests to package tests with something like rollup-plugin-relative-to-package
• You don't want to manually maintain dependencies in the package.json file for your package tests

Installation

Using npm:

npm install --save-dev rollup-plugin-create-test-package-json

Use

The file rollup.test.config.js in this package provides a complete working example that validates this package before release. If you have pnpm installed, you can run it like this:

# Requires pnpm
# Only tested on Linux
pnpm run check:packfile

You can use npm if you change pnpm to npm in rollup.test.config.js.

Options

The plugin works without options. You will almost certainly want to use the testPackageJson option so you can specify a scripts section and perhaps a devDependencies section for your test runner.

jsonWriter

• Type: AsyncFunction
• Default: a function that pretty prints testPackageJson

Use jsonWriter if you don't like how this plugin writes package.json by default. The parameters are:

• path - the full path name of the package.json file. For example: /tmp/package-test-451/package.json
• testPackageJson - the package.json Object that the plugin is writing

This is more or less what the default function looks like:

import fs from 'fs-extra'
const defaultJsonWriter = async (path, json) => fs.writeJSON(path, json, { spaces: 2 })

packageJson

• Type: Object|Promise
• Default: the local package.json from disk

This is the package.json of the package you are testing. If your package's package.json isn't suitable, you can use this option. If you set this option, the plugin will not read from the filesystem at all. This option exists primarily to support unit testing.

You can pass a Promise that resolves to a package.json file if you want. That way, you can do some async configuration work in your rollup.config.js

rootDir

• Type: String
• Default: process.cwd()

This option tells the plugin where to look for the project's package.json if the packageJson option is not specified. This plugin will start looking for a package.json at rootDir and walk up the directory structure until it finds one, or fails at the root directly.

testPackageJson

• Type: Object|Promise
• Default: boilerplate package.json

This plugin automatically grabs dependencies from the generated unit tests, and picks up the version specifiers from package.json. However, it doesn't know how to run your unit tests. Specify the parts of the package.json required to run the unit tests with this option. Anything you specify will override the values generated by the plugin.

You can pass a Promise that resolves to an Object if you want. That way, you can do some async configuration work in your rollup.config.js

Here's an example. If you provide:

  testPackageJson: {
    name: 'awesome-test-package' // copied over directly
    scripts: { test: 'tape -r esm test/**/*.js' }, // copied over directly
    customField: 'whatever', // copied over directly
    dependencies: {
      'lodash': '^5.0.0' // will override the value read from packageJson
    }
    devDependencies: { // devDependencies copied over directly
      "esm": "^3.2.25",
      "tape": "^4.13.2"
    }
  }

But your package's package.json says this:

  "depencencies": {
    "lodash": "^4.17.15"
  }

This plugin will use '^5.0.0' instead of '^4.17.15' for lodash in the generated package.json. It would have used '^4.17.15' from the packageJson option by default.

Contributing

So far, this plugin has only been tested on Linux. Contributions are very welcome. Please create a pull request or write up an issue. This package uses the pnpm package manager. Run pnpm run check to run all the unit tests and validation scripts. You can use npm if you change pnpm to npm in rollup.test.config.js.

Issues

This project uses Github issues.

License

MIT