feat: improve tests

Author: alexander-akait

templates/test/fixtures/foo.js

@@ -1 +1 @@
-console.log('foo');
+export default 'foo';

templates/test/fixtures/simple.js

@@ -1,3 +1,5 @@
 import foo from './foo';
 
+__export__ = foo;
+
 export default foo;

templates/test/helpers/execute.js

@@ -0,0 +1,22 @@
+import Module from 'module';
+import path from 'path';
+
+const parentModule = module;
+
+export default (code) => {
+  const resource = 'test.js';
+  const module = new Module(resource, parentModule);
+  // eslint-disable-next-line no-underscore-dangle
+  module.paths = Module._nodeModulePaths(
+    path.resolve(__dirname, '../fixtures')
+  );
+  module.filename = resource;
+
+  // eslint-disable-next-line no-underscore-dangle
+  module._compile(
+    `let __export__;${code};module.exports = __export__;`,
+    resource
+  );
+
+  return module.exports;
+};

templates/test/helpers/getCompiler.js

@@ -1,7 +1,7 @@
 import path from 'path';
 
 import webpack from 'webpack';
-import memfs from 'memfs';
+import { createFsFromVolume, Volume } from 'memfs';
 
 export default (fixture, loaderOptions = {}, config = {}) => {
   const fullConfig = {
@@ -34,9 +34,7 @@ export default (fixture, loaderOptions = {}, config = {}) => {
   const compiler = webpack(fullConfig);
 
   if (!config.outputFileSystem) {
-    const outputFileSystem = memfs;
-
-    outputFileSystem.vol.reset();
+    const outputFileSystem = createFsFromVolume(new Volume());
     // Todo remove when we drop webpack@4 support
     outputFileSystem.join = path.join.bind(path);
 

templates/test/loader.test.js

@@ -1,13 +1,19 @@
-import { getCompiler, compile, normalizeErrors, readAsset } from './helpers';
+import {
+  compile,
+  execute,
+  getCompiler,
+  normalizeErrors,
+  readAsset,
+} from './helpers';
 
 describe('loader', () => {
   it('should work', async () => {
     const compiler = getCompiler('simple.js');
     const stats = await compile(compiler);
 
-    expect(readAsset('main.bundle.js', compiler, stats)).toMatchSnapshot(
-      'result'
-    );
+    expect(
+      execute(readAsset('main.bundle.js', compiler, stats))
+    ).toMatchSnapshot('result');
     expect(normalizeErrors(stats.compilation.warnings)).toMatchSnapshot(
       'warnings'
     );