Fix tests in template project (0.58-stable) (facebook#23128)

* Restore __tests__ folder in HelloWorld template

PR facebook#18019 Removed __tests__ and __fixtures__ folders from npm package.
But it also effectively removed __tests__ folder from initial project
template. This commit restores __tests__ in template application.

It applicable only to 0.58-stable branch because in master, templates
was moved to another location. I think we should recheck what is ignored
in master after this landed.

* Use babel.config.js in template HelloWorld application

* Add babel-core@^7.0.0-bridge.0 to jest dependencies when react-native init new project. This should fix tests with babel7.

local-cli/.npmignore

@@ -1,2 +1,3 @@
 __fixtures__
 __tests__
+!/templates/HelloWorld/__tests__

local-cli/generator/copyProjectTemplateAndReplace.js

@@ -127,6 +127,7 @@ function translateFilePath(path) {
     .replace('_BUCK', 'BUCK')
     .replace('_gitignore', '.gitignore')
     .replace('_gitattributes', '.gitattributes')
+    .replace('_babel.config.js', 'babel.config.js')
     .replace('_babelrc', '.babelrc')
     .replace('_flowconfig', '.flowconfig')
     .replace('_buckconfig', '.buckconfig')

local-cli/init/init.js

@@ -90,7 +90,7 @@ function generateProject(destinationRoot, newProjectName, options) {
     });
   }
   if (!options['skip-jest']) {
-    const jestDeps = `jest babel-jest metro-react-native-babel-preset react-test-renderer@${reactVersion}`;
+    const jestDeps = `jest babel-core@^7.0.0-bridge.0 babel-jest metro-react-native-babel-preset react-test-renderer@${reactVersion}`;
     if (yarnVersion) {
       console.log('Adding Jest...');
       execSync(`yarn add ${jestDeps} --dev --exact`, {stdio: 'inherit'});

local-cli/templates/HelloWorld/_babel.config.js

@@ -0,0 +1,3 @@
+module.exports = {
+  presets: ["module:metro-react-native-babel-preset"]
+}