test: external css using HTML-compliant syntax

Author: Jakub Freisler

e2e/__projects__/style/components/External.vue

@@ -8,6 +8,8 @@
 
 <style module="$style2" src="~__styles/external.css" />
 
+<style module="$style3" src="./styles/external.css"></style>
+
 <style module="css">
 .a {
   background: color(red a(90%));

e2e/__projects__/style/test.js

@@ -46,5 +46,6 @@ test('process External', () => {
   expect(wrapper.vm).toBeTruthy()
   expect(wrapper.vm.$style.testClass).toEqual('testClass')
   expect(wrapper.vm.$style2.testClass).toEqual('testClass')
+  expect(wrapper.vm.$style3.testClass).toEqual('testClass')
   expect(wrapper.vm.css.a).toEqual('a')
 })