feat: improve component based tests approach (#5923)

- new mode that mounts the spec iframe instead of application iframe

scripts/unit/binary/util/packages-spec.js

@@ -15,6 +15,7 @@ const { expect } = chai
 const packages = require('../../../binary/util/packages')
 const { transformRequires } = require('../../../binary/util/transform-requires')
 const { testPackageStaticAssets } = require('../../../binary/util/testStaticAssets')
+const externalUtils = require('../../../binary/util/3rd-party')
 
 global.beforeEach(() => {
   mockfs.restore()
@@ -40,7 +41,19 @@ describe('packages', () => {
       },
     })
 
-    await packages.copyAllToDist(os.tmpdir())
+    sinon.stub(externalUtils, 'globby')
+    .withArgs(['package.json', 'lib', 'src/main.js'])
+    .resolves([
+      'package.json',
+      'lib/foo.js',
+      'src/main.js',
+    ])
+
+    const destinationFolder = os.tmpdir()
+
+    debug('destination folder %s', destinationFolder)
+
+    await packages.copyAllToDist(destinationFolder)
 
     const files = getFs()