test: fix

README.md

@@ -562,7 +562,7 @@ Default: `false`
 
 > **Note**
 >
-> This options will work only when you set `namedExport` to `true` in `css-loader`
+> This option will work only when you set `namedExport` to `true` in `css-loader`
 
 By default, `mini-css-extract-plugin` generates JS modules based on the `esModule` and `namedExport` options in `css-loader`.
 Using the `esModule` and `namedExport` options will allow you to better optimize your code.

test/__snapshots__/validate-loader-options.test.js.snap

@@ -1,5 +1,12 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
+exports[`validate options should throw an error on the "defaultExport" option with "1" value 1`] = `
+"Invalid options object. Mini CSS Extract Plugin Loader has been initialized using an options object that does not match the API schema.
+ - options.defaultExport should be a boolean.
+   -> Duplicate the named export with CSS modules locals to the default export (only when \`esModules: true\` for css-loader).
+   -> Read more at https://github.com/webpack-contrib/mini-css-extract-plugin#defaultexports"
+`;
+
 exports[`validate options should throw an error on the "esModule" option with "1" value 1`] = `
 "Invalid options object. Mini CSS Extract Plugin Loader has been initialized using an options object that does not match the API schema.
  - options.esModule should be a boolean.