diff --git a/tasks/cra.js b/tasks/cra.js
index ec15d702ac517357cb8bac74a5bd7d0b60d92093..c181a23561c3326bbed156f610f608229a99a5cd 100644
--- a/tasks/cra.js
+++ b/tasks/cra.js
@@ -14,6 +14,8 @@ const cp = require('child_process');
 
 const cleanup = () => {
   console.log('Cleaning up.');
+  // Reset changes made to package.json files.
+  cp.execSync(`git checkout -- packages/*/package.json`);
   // Uncomment when snapshot testing is enabled by default:
   // rm ./template/src/__snapshots__/App.test.js.snap
 };
@@ -25,7 +27,8 @@ const handleExit = () => {
 };
 
 const handleError = e => {
-  console.error('ERROR! An error was encountered while executing\n', e);
+  console.error('ERROR! An error was encountered while executing');
+  console.error(e);
   cleanup();
   console.log('Exiting with error.');
   process.exit(1);
@@ -34,69 +37,81 @@ const handleError = e => {
 process.on('SIGINT', handleExit);
 process.on('uncaughtException', handleError);
 
-// ******************************************************************************
-// Pack react- scripts so we can verify they work.
-// ******************************************************************************
+console.log();
+console.log('-------------------------------------------------------');
+console.log('Assuming you have already run `yarn` to update the deps.');
+console.log('If not, remember to do this before testing!');
+console.log('-------------------------------------------------------');
+console.log();
 
-const rootDir = path.join(__dirname, '..');
-const reactScriptsDir = path.join(rootDir, 'packages', 'react-scripts');
-const packageJsonPath = path.join(reactScriptsDir, 'package.json');
-const packageJsonOrigPath = path.join(reactScriptsDir, 'package.json.orig');
-
-// Install all our packages
-const lernaPath = path.join(rootDir, 'node_modules', '.bin', 'lerna');
-cp.execSync(`${lernaPath} bootstrap`, {
-  cwd: rootDir,
-  stdio: 'inherit',
-});
+// Temporarily overwrite package.json of all packages in monorepo
+// to point to each other using absolute file:/ URLs.
 
-// Save package.json because we're going to touch it
-fs.writeFileSync(packageJsonOrigPath, fs.readFileSync(packageJsonPath));
+const gitStatus = cp.execSync(`git status --porcelain`).toString();
 
-// Replace own dependencies (those in the`packages` dir) with the local paths
-// of those packages
-const replaceOwnDepsPath = path.join(__dirname, 'replace-own-deps.js');
-cp.execSync(`node ${replaceOwnDepsPath}`, { stdio: 'inherit' });
+if (gitStatus.trim() !== '') {
+  console.log('Please commit your changes before running this script!');
+  console.log('Exiting because `git status` is not empty:');
+  console.log();
+  console.log(gitStatus);
+  console.log();
+  process.exit(1);
+}
+
+const rootDir = path.join(__dirname, '..');
+const packagesDir = path.join(rootDir, 'packages');
+const packagePathsByName = {};
+fs.readdirSync(packagesDir).forEach(name => {
+  const packageDir = path.join(packagesDir, name);
+  const packageJson = path.join(packageDir, 'package.json');
+  if (fs.existsSync(packageJson)) {
+    packagePathsByName[name] = packageDir;
+  }
+});
+Object.keys(packagePathsByName).forEach(name => {
+  const packageJson = path.join(packagePathsByName[name], 'package.json');
+  const json = JSON.parse(fs.readFileSync(packageJson, 'utf8'));
+  Object.keys(packagePathsByName).forEach(otherName => {
+    if (json.dependencies && json.dependencies[otherName]) {
+      json.dependencies[otherName] = 'file:' + packagePathsByName[otherName];
+    }
+    if (json.devDependencies && json.devDependencies[otherName]) {
+      json.devDependencies[otherName] = 'file:' + packagePathsByName[otherName];
+    }
+    if (json.peerDependencies && json.peerDependencies[otherName]) {
+      json.peerDependencies[otherName] =
+        'file:' + packagePathsByName[otherName];
+    }
+    if (json.optionalDependencies && json.optionalDependencies[otherName]) {
+      json.optionalDependencies[otherName] =
+        'file:' + packagePathsByName[otherName];
+    }
+  });
+
+  fs.writeFileSync(packageJson, JSON.stringify(json, null, 2), 'utf8');
+  console.log(
+    'Replaced local dependencies in packages/' + name + '/package.json'
+  );
+});
+console.log('Replaced all local dependencies for testing.');
+console.log('Do not edit any package.json while this task is running.');
 
-// Finally, pack react-scripts
+// Finally, pack react-scripts.
 // Don't redirect stdio as we want to capture the output that will be returned
 // from execSync(). In this case it will be the .tgz filename.
 const scriptsFileName = cp
-  .execSync(`npm pack`, { cwd: reactScriptsDir })
+  .execSync(`npm pack`, { cwd: path.join(packagesDir, 'react-scripts') })
   .toString()
   .trim();
-const scriptsPath = path.join(
-  rootDir,
-  'packages',
-  'react-scripts',
-  scriptsFileName
-);
-
-// Restore package.json
-fs.unlinkSync(packageJsonPath);
-fs.writeFileSync(packageJsonPath, fs.readFileSync(packageJsonOrigPath));
-fs.unlinkSync(packageJsonOrigPath);
+const scriptsPath = path.join(packagesDir, 'react-scripts', scriptsFileName);
 
-// ******************************************************************************
 // Now that we have packed them, call the global CLI.
-// ******************************************************************************
-
-// If Yarn is installed, clean its cache because it may have cached react-scripts
-try {
-  cp.execSync('yarn cache clean');
-} catch (e) {
-  // We can safely ignore this as the user doesn't have yarn installed
-}
+cp.execSync('yarn cache clean');
 
 const args = process.argv.slice(2);
 
 // Now run the CRA command
-const craScriptPath = path.join(
-  rootDir,
-  'packages',
-  'create-react-app',
-  'index.js'
-);
+const craScriptPath = path.join(packagesDir, 'create-react-app', 'index.js');
 cp.execSync(
   `node ${craScriptPath} --scripts-version="${scriptsPath}" ${args.join(' ')}`,
   {
diff --git a/tasks/replace-own-deps.js b/tasks/replace-own-deps.js
deleted file mode 100755
index 15d53d9dc8609006e01ccd2decefb8229d5bc847..0000000000000000000000000000000000000000
--- a/tasks/replace-own-deps.js
+++ /dev/null
@@ -1,30 +0,0 @@
-#!/usr/bin/env node
-/**
- * Copyright (c) 2015-present, Facebook, Inc.
- *
- * This source code is licensed under the MIT license found in the
- * LICENSE file in the root directory of this source tree.
- */
-'use strict';
-
-// Replaces internal dependencies in package.json with local package paths.
-
-const fs = require('fs');
-const path = require('path');
-
-const packagesDir = path.join(__dirname, '../packages');
-const pkgFilename = path.join(packagesDir, 'react-scripts/package.json');
-const data = require(pkgFilename);
-
-fs.readdirSync(packagesDir).forEach(name => {
-  if (data.dependencies[name]) {
-    data.dependencies[name] = 'file:' + path.join(packagesDir, name);
-  }
-});
-
-fs.writeFile(pkgFilename, JSON.stringify(data, null, 2), 'utf8', err => {
-  if (err) {
-    throw err;
-  }
-  console.log('Replaced local dependencies.');
-});