write compiled output to disk for easier inspection

.gitignore

@@ -23,6 +23,7 @@ node_modules
 /test/sourcemaps/samples/*/output.css.map
 /yarn-error.log
 _actual*.*
+_output
 /types
 
 /site/cypress/screenshots/

test/helpers.js

@@ -1,6 +1,7 @@
 import * as jsdom from 'jsdom';
 import * as assert from 'assert';
 import * as glob from 'tiny-glob/sync.js';
+import * as path from 'path';
 import * as fs from 'fs';
 import * as colors from 'kleur';
 
@@ -237,3 +238,16 @@ export function useFakeTimers() {
 		}
 	};
 }
+
+export function mkdirp(dir) {
+	const parent = path.dirname(dir);
+	if (parent === dir) return;
+
+	mkdirp(parent);
+
+	try {
+		fs.mkdirSync(dir);
+	} catch (err) {
+		// do nothing
+	}
+}

test/runtime/index.js

@@ -3,6 +3,7 @@ import * as path from "path";
 import * as fs from "fs";
 import { rollup } from 'rollup';
 import * as virtual from 'rollup-plugin-virtual';
+import * as glob from 'tiny-glob/sync.js';
 import { clear_loops, flush, set_now, set_raf } from "../../internal";
 
 import {
@@ -10,7 +11,8 @@ import {
 	loadConfig,
 	loadSvelte,
 	env,
-	setupHtmlEqual
+	setupHtmlEqual,
+	mkdirp
 } from "../helpers.js";
 
 let svelte$;
@@ -90,6 +92,33 @@ describe("runtime", () => {
 
 			const window = env();
 
+			glob('**/*.svelte', { cwd }).forEach(file => {
+				if (file[0] === '_') return;
+
+				const dir  = `${cwd}/_output/${hydrate ? 'hydratable' : 'normal'}`;
+				const out = `${dir}/${file.replace(/\.svelte$/, '.js')}`;
+
+				if (fs.existsSync(out)) {
+					fs.unlinkSync(out);
+				}
+
+				mkdirp(dir);
+
+				try {
+					const { js } = compile(
+						fs.readFileSync(`${cwd}/${file}`, 'utf-8'),
+						{
+							...compileOptions,
+							filename: file
+						}
+					);
+
+					fs.writeFileSync(out, js.code);
+				} catch (err) {
+					// do nothing
+				}
+			});
+
 			return Promise.resolve()
 				.then(() => {
 					// hack to support transition tests
@@ -195,7 +224,7 @@ describe("runtime", () => {
 					} else {
 						throw err;
 					}
-				 }).catch(err => {
+				}).catch(err => {
 					failed.add(dir);
 					showOutput(cwd, compileOptions, compile); // eslint-disable-line no-console
 					throw err;