Add yarn test-bundles and yarn test-prod-bundles

Only files ending with -test.public.js are opted in (so far we don't have any).

package.json

@@ -105,6 +105,8 @@
     "postinstall": "node node_modules/fbjs-scripts/node/check-dev-engines.js package.json",
     "test": "cross-env NODE_ENV=development jest --config ./scripts/jest/config.source.js",
     "test-prod": "cross-env NODE_ENV=production jest --config ./scripts/jest/config.source.js",
+    "test-bundles": "cross-env NODE_ENV=development jest --config ./scripts/jest/config.bundles.js",
+    "test-bundles-prod": "cross-env NODE_ENV=production jest --config ./scripts/jest/config.bundles.js",
     "flow": "node ./scripts/tasks/flow.js",
     "prettier": "node ./scripts/prettier/index.js write-changed",
     "prettier-all": "node ./scripts/prettier/index.js write",

scripts/jest/config.bundles.js

@@ -0,0 +1,33 @@
+'use strict';
+
+const {readdirSync, statSync} = require('fs');
+const {join} = require('path');
+const sourceConfig = require('./config.source');
+
+// Find all folders in packages/* with package.json
+const packagesRoot = join(__dirname, '..', '..', 'packages');
+const packages = readdirSync(packagesRoot).filter(dir => {
+  if (dir.charAt(0) === '.') {
+    return false;
+  }
+  const packagePath = join(packagesRoot, dir, 'package.json');
+  return statSync(packagePath).isFile();
+});
+// Create a module map to point React packages to the build output
+const moduleNameMapper = {};
+packages.forEach(name => {
+  // Root entry point
+  moduleNameMapper[`^${name}$`] = `<rootDir>/build/packages/${name}`;
+  // Named entry points
+  moduleNameMapper[`^${name}/(.*)$`] = `<rootDir>/build/packages/${name}/$1`;
+});
+
+module.exports = Object.assign({}, sourceConfig, {
+  // Redirect imports to the compiled bundles
+  moduleNameMapper,
+  // Only run bundle tests on whitelisted .public.* files
+  // TODO: switch to a blacklist instead when enough tests are opted in
+  testRegex: '/__tests__/.*\\.public\\.js$',
+  // Exclude the build output from transforms
+  transformIgnorePatterns: ['/node_modules/', '<rootDir>/build/'],
+});