Add a test with same packageName and fileName (#7517)

tests_integration/plugins/automatic/node_modules/prettier-plugin-bar/index.js

@@ -1,7 +1,7 @@
 "use strict";
 
 const prettier = require("prettier/local");
-const concat = prettier.doc.builders.concat;
+const { concat } = prettier.doc.builders;
 
 module.exports = {
   languages: [
@@ -18,7 +18,11 @@ module.exports = {
   },
   printers: {
     bar: {
-      print: path => concat(["bar+", path.getValue().text])
+      print: path =>
+        concat([
+          "content from `prettier-plugin-bar` package + ",
+          path.getValue().text
+        ])
     }
   },
   defaultOptions: {