Fix external source filename

Author: jolting

lib/process.js

@@ -31,19 +31,19 @@ function processScript(scriptPart, filePath, config) {
     return null
   }
 
-  let externalSrc = null
+  let content = scriptPart.content
+  let filename = filePath
   if (scriptPart.src) {
-    scriptPart.content = loadSrc(scriptPart.src, filePath)
-    externalSrc = scriptPart.content
+    content = loadSrc(scriptPart.src, filePath)
+    filename = scriptPart.src
   }
 
   const vueJestConfig = getVueJestConfig(config)
   const transformer = resolveTransformer(scriptPart.lang, vueJestConfig)
 
-  const result = transformer.process(scriptPart.content, filePath, config)
+  const result = transformer.process(content, filename, config)
   result.code = stripInlineSourceMap(result.code)
   result.map = mapLines(scriptPart.map, result.map)
-  result.externalSrc = externalSrc
   return result
 }