// rollup.config.js
import command from 'rollup-plugin-command';
export default {
	// ...
	plugins: [
		// ...
		command(`node tests.js`, options),
	],
	// ...
};

command(require('tests.js'));

command(
	[
		`npm test`, // The next command will not be executed until this
		// one is finished.
		require('./scripts/cleanup').someFunc, // If this returns a
		// promise, and `options.wait` is true (it's false by default), this
		// plugin will wait for it to be resolved before moving on to the
		// next command or finishing the build.
	],
	{ exitOnFail: true }
); // Default for options.exitOnFail is false.