Add tests for page hook

test/node_modules/gitbook-plugin-test-hooks/index.js

@@ -1,5 +1,3 @@
-var should = require('should');
-
 module.exports = {
     hooks: {
         'init': function() {
@@ -11,6 +9,10 @@ module.exports = {
         },
         'finish:before': function() {
             global._hooks.push('finish:before');
+        },
+        page: function(page) {
+            page.content = 'Hello ' + page.content;
+            return page;
         }
     }
 };