Fix tests bundling

package.json

@@ -25,7 +25,10 @@
     "test-main": "electron-mocha --require source-map-support/register app/main.specs.js",
     "test-renderer": "electron-mocha --require source-map-support/register --renderer app/renderer.specs.js",
     "test": "npm-run-all test-main test-renderer",
-    "coverage": "npm test -- -R scripts/istanbul-reporter",
+    "precoverage": "gulp build-coverage-tests --env=test",
+    "coverage-main": "electron-mocha --require source-map-support/register --reporter scripts/istanbul-reporter app/main.specs.js",
+    "coverage-renderer": "electron-mocha --require source-map-support/register --reporter scripts/istanbul-reporter app/renderer.specs.js",
+    "coverage": "npm-run-all coverage-main coverage-renderer",
     "pree2e": "gulp build-e2e-tests --env=test",
     "e2e": "mocha app/e2e.js.autogenerated --require source-map-support/register"
   },

tasks/build-tests.js

 const gulp = require('gulp');
-const jetpack = require('fs-jetpack');
 const bundle = require('./bundle');
-const istanbul = require('rollup-plugin-istanbul');
 
-const createEntryFile = async(srcDir, matching, outputDir, entryFileName, rollupOptions) => {
-	const entryFileContent = srcDir.find('.', { matching })
-		.map((path) => `import './${ path.replace(/\\/g, '/') }';`)
-		.join('\n');
 
-	srcDir.write(entryFileName, entryFileContent);
-
-	await bundle(srcDir.path(entryFileName), outputDir.path(entryFileName), rollupOptions);
-
-	srcDir.remove(entryFileName);
-};
-
-gulp.task('build-unit-tests', ['environment'], () => {
-	const rollupOptions = {
-		rollupPlugins: [
-			istanbul({
-				exclude: ['**/*.spec.js', '**/*.specs.js'],
-				sourcemap: true,
-			}),
-		],
-	};
+gulp.task('build-unit-tests', ['build-app'], async() => {
+	await bundle.many('src', 'background/*.spec.js', 'app/main.specs.js');
+	await bundle.many('src', ['*.spec.js', '!background/*.spec.js'], 'app/renderer.specs.js');
+});
 
-	return Promise.all([
-		createEntryFile(jetpack.cwd('src'), 'background/*.spec.js',
-			jetpack.cwd('app'), 'main.specs.js', rollupOptions),
-		createEntryFile(jetpack.cwd('src'), ['*.spec.js', '!background/*.spec.js'],
-			jetpack.cwd('app'), 'renderer.specs.js', rollupOptions),
-	]);
+gulp.task('build-coverage-tests', ['build-app'], async() => {
+	await bundle.many('src', 'background/*.spec.js', 'app/main.specs.js', { coverage: true });
+	await bundle.many('src', ['*.spec.js', '!background/*.spec.js'], 'app/renderer.specs.js', { coverage: true });
 });
 
-gulp.task('build-e2e-tests', ['build-app'], () => createEntryFile(
-	jetpack.cwd('src'), '*.e2e.js',
-	jetpack.cwd('app'), 'e2e.js.autogenerated'
-));
+gulp.task('build-e2e-tests', ['build-app'], async() => {
+	await bundle.many('src', '*.e2e.js', 'app/e2e.js.autogenerated');
+});

tasks/bundle.js

-const path = require('path');
 const builtinModules = require('builtin-modules');
-const appManifest = require('../package.json');
+const jetpack = require('fs-jetpack');
+const path = require('path');
 const { rollup } = require('rollup');
+const commonjs = require('rollup-plugin-commonjs');
+const istanbul = require('rollup-plugin-istanbul');
 const json = require('rollup-plugin-json');
 const nodeResolve = require('rollup-plugin-node-resolve');
-const commonjs = require('rollup-plugin-commonjs');
+const appManifest = require('../package.json');
 
 
 const cached = {};
 
-module.exports = async(src, dest, { rollupPlugins = [] } = {}) => {
+const bundle = async(src, dest, { coverage = false, rollupPlugins = [] } = {}) => {
 	const inputOptions = {
 		input: src,
 		external: [
@@ -20,6 +22,12 @@ module.exports = async(src, dest, { rollupPlugins = [] } = {}) => {
 		cache: cached[src],
 		plugins: [
 			...rollupPlugins,
+			...(coverage ? [
+				istanbul({
+					exclude: ['**/*.spec.js', '**/*.specs.js'],
+					sourcemap: true,
+				}),
+			] : []),
 			json(),
 			nodeResolve(),
 			commonjs(),
@@ -39,3 +47,19 @@ module.exports = async(src, dest, { rollupPlugins = [] } = {}) => {
 	cached[src] = bundle;
 	await bundle.write(outputOptions);
 };
+
+const bundleMany = async(srcDirPath, matching, dest, options) => {
+	const srcDir = jetpack.cwd(srcDirPath);
+	const src = srcDir.path(path.basename(dest));
+
+	const entryFileContent = (await srcDir.findAsync({ matching }))
+		.map((path) => `import './${ path.replace(/\\/g, '/') }';`)
+		.join('\n');
+
+	await jetpack.writeAsync(src, entryFileContent);
+	await bundle(src, dest, options);
+	await jetpack.removeAsync(src);
+};
+
+module.exports = bundle;
+module.exports.many = bundleMany;