fix tests

src/server/generateServerInjector.js

@@ -2,7 +2,7 @@ import titleGenerator from './generators/titleGenerator'
 import attrsGenerator from './generators/attrsGenerator'
 import tagGenerator from './generators/tagGenerator'
 
-export default function _generateServerInjector (options) {
+export default function _generateServerInjector (options = {}) {
   /**
    * Converts a meta info property to one that can be stringified on the server
    *

src/server/generators/attrsGenerator.js

@@ -1,4 +1,6 @@
-export default function _attrsGenerator ({ attribute }) {
+export default function _attrsGenerator (options = {}) {
+  const { attribute } = options
+
   /**
    * Generates tag attributes for use on the server.
    *

src/server/generators/tagGenerator.js

@@ -1,4 +1,6 @@
-export default function _tagGenerator ({ attribute }) {
+export default function _tagGenerator (options = {}) {
+  const { attribute } = options
+
   /**
    * Generates meta, base, link, style, script, noscript tags for use on the server
    *

src/server/generators/titleGenerator.js

@@ -1,4 +1,6 @@
-export default function _titleGenerator ({ attribute }) {
+export default function _titleGenerator (options = {}) {
+  const { attribute } = options
+
   /**
    * Generates title output for the server
    *

src/server/inject.js

@@ -1,7 +1,7 @@
 import getMetaInfo from '../shared/getMetaInfo'
 import generateServerInjector from './generateServerInjector'
 
-export default function _inject (options) {
+export default function _inject (options = {}) {
   /**
    * Converts the state of the meta info object such that each item
    * can be compiled to a tag string on the server