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 creates that package.json file for you. It is intended to be used in conjunction with rollup-plugin-relative-to-package which converts your unit tests to package tests.

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 maintain dependencies in the package.json file for your package tests

This plugin makes the package.json for your test package while rollup-plugin-relative-to-package is converting unit tests to package tests. For example rollup-plugin-relative-to-package will convert the unit test:

import YourPackage from '../src/your-package-module'
import { internalFunction } from '../src/inside-your-package'
import { test } from 'zora'
import { chainable } from 'iterablefu'
/* Unit test code goes here */

To this:

import YourPackage from 'your-package-name'
import { internalFunction } from 'your-package-name/src/inside-your-package'
import { test } from 'zora'
import { chainable } from 'iterablefu'
/* Unit test code goes here */

While Rollup is working, this plugin, rollup-plugin-create-test-package-json, will pick up the unit test dependencies your-package-name, zora, and iterablefu. It will put those dependencies into the test package's package.json using version numbers from your package's package.json. The dependency on your-package-name is for a pack file by default.

Depending on your options, the generated package.json for your test package (not your package) would look something like this:

{
  "name": "your-package-name-package-test",
  "version": "1.0.0",
  "description": "Generated package test for your-package-name",
  "main": "index.js",
  "scripts": {
    "test": "tape -r esm test/*_test.js"
  },
  "author": "rollup-plugin-test-package-json",
  "dependencies": {
    "your-package-name": "file:your-package-name-0.1.0-alpha05.tgz",
    "zora": "^3.1.8",
    "iterablefu": "^0.4.1",
  },
  "devDependencies": {
    "esm": "^3.2.25",
    "tape": "^4.13.2"
  }
}

Installation

Using npm:

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

Use

Here's a complete example showing how to use this plugin with other plugins to produce package tests and a package.json file.

import createTestPackageJson from 'rollup-plugin-create-test-package-json'
import relativeToPackage from 'rollup-plugin-relative-to-package'
import multiInput from 'rollup-plugin-multi-input'

export default [
  {
    // Each unit test is a separate entry point.
    // Using multiInput to handle an input glob
    // We're using Rollup on the unit tests - not the package source!!
    input: ['test/**/*_test.js'],
    // Set this if you want each unit test output separately
    preserveModules: true,
    output: {
      // The test runner is using 'esm' to load ES modules,
      // so conversion to cjs is NOT required
      format: 'es',
      // This plugin will put package.json here
      // and Rollup will put the transformed unit tests here
      dir: 'tempdir/somewhere/for/test/package'

      // The plugin will use 'file' if you provide that instead.
      // file: 'tempdir/a/single/test/file.js'
    },
    plugins: [
      multiInput(), // Handles the input glob above
      // relativeToPackage converts unit tests to package tests
      relativeToPackage({
        modulePaths: 'src/**/*.js' // The package source is here
      }),
      // createTestPackageJson creates the package.json file
      createTestPackageJson({
        // Override defaults by providing fields you
        // want in your test package.json file.
        testPackageJson: {
          // Specify this so 'npm test' works
          scripts: {
            test: 'tape -r esm test/*_test.js'
          },
          // dependencies for the test runner only
          devDependencies: {
            esm: '^3.2.25',
            tape: '^4.13.2'
          }
        }
      })
    ]
  }
]

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 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.

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

Specify any fields you want to appear in the generated package.json file. Anything you specify will override the plugin's values. This plugin will generate the dependencies section and merge in the dependencies section you provide on top of the generated one. The generated dependency versions are read from the packageJson option.

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 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' in the generated package.json. It would have used '^4.17.15' from the packageJson option by default.