rollup.test.config.js

import runCommands, { shellCommand } from '@toolbuilder/rollup-plugin-commands'
import createPackFile from '@toolbuilder/rollup-plugin-create-pack-file'
import { tmpdir } from 'os'
import { join } from 'path'
import { globSync } from 'glob'
import createTestPackageJson from 'rollup-plugin-create-test-package-json'
import path from 'node:path'
import { fileURLToPath } from 'node:url'

/*
  This Rollup configuration is used by the 'check:packfile' script to validate that the
  packfile can pass the unit tests. It assumes 'pnpm' is installed. You can use 'npm' by
  changing 'pnpm' to 'npm' in this configuration.

  Use this configuration by running 'pnpm run check:packfile'. It will:
  1. Create a temporary directory in your system's temporary directory structure
  2. Place the converted unit tests in the temporary directory
  3. Build a node package.json in the temporary directory
  4. Install the required dependencies
  5. Run the modified unit test on the packfile of this package
*/

// This is recommended way of preserving directory structure and processing all files
// rather than using 'preserveModules: true', which involves tree-shaking and virtual files
const mapInputs = (glob) => Object.fromEntries(
  globSync(glob).map(file => [
    // Provide <dir structure>/<file basename> relative to package root, no file extension
    path.relative('.', file.slice(0, file.length - path.extname(file).length)),
    // Provide absolute filepath of input file
    fileURLToPath(new URL(file, import.meta.url))
  ])
)

// This is where the test package is created
const testPackageDir = join(tmpdir(), `${Date.now()}`)

export default [
  {
    input: mapInputs(['test/plugin.test.js', 'test/exports-resolve.test.js']),
    // Sometimes Rollup provides an absolute path to an 'internal' file such as './test/make-package-json.js'
    external: (id) => !(id.startsWith('.') || id.startsWith('/')),
    output: {
      format: 'es',
      dir: testPackageDir,
      preserveModules: false
    },
    plugins: [
      createTestPackageJson({ // Creates package.json for testPackageDir
        // Provide information that plugin can't pick up for itself
        testPackageJson: {
          type: 'module',
          scripts: {
            test: 'pta --reporter tap "test/**/*test.js"'
          },
          // dependencies are populated automatically based on unit test imports
          devDependencies: {
            // These are the dependencies for the test runner
            pta: '^1.3.0',
            zora: '^6.0.0'
          }
        }
      }),
      createPackFile({ // and move it to output.dir (i.e. testPackageDir)
        packCommand: 'pnpm pack'
      }),
      runCommands({
        commands: [
          // Install dependencies and run the unit test
          // The -C parameter ensures that the test does not resolve
          // any packages outside testPackageDir. Ordinarily, it
          // would pickup packages in this package too.
          shellCommand(`pnpm -C ${testPackageDir} install-test`)
        ]
      })
    ]
  }
]