Do not test for null in required plugin.

Comment out corresponding test spec.

Author: tmpfs

plugin/util/required.js

@@ -7,7 +7,7 @@ module.exports = function() {
     if(!this.isRoot()
       && this.rule.required
       && (!this.source.hasOwnProperty(this.field)
-        || this.value === undefined || this.value === null)) {
+        || this.value === undefined)) {
       this.raise(
         this.reasons.required,
         this.messages.required, this.field);

test/spec/string.js

@@ -19,21 +19,21 @@ describe('async-validate:', function() {
     });
   });
 
-  it('should error on required string field (null)', function(done) {
-    var descriptor = {
-      type: 'object',
-      fields: {
-        name: {type: 'string', required: true}
-      }
-    }
-    var schema = new Schema(descriptor);
-    schema.validate({name: null}, function(err, res) {
-      expect(res.errors.length).to.eql(2);
-      expect(res.fields.name.length).to.eql(2);
-      expect(res.errors[0].message).to.eql('name is required');
-      done();
-    });
-  });
+  //it('should error on required string field (null)', function(done) {
+    //var descriptor = {
+      //type: 'object',
+      //fields: {
+        //name: {type: 'string', required: true}
+      //}
+    //}
+    //var schema = new Schema(descriptor);
+    //schema.validate({name: null}, function(err, res) {
+      //expect(res.errors.length).to.eql(2);
+      //expect(res.fields.name.length).to.eql(2);
+      //expect(res.errors[0].message).to.eql('name is required');
+      //done();
+    //});
+  //});
 
   it('should error on non-string type', function(done) {
     var descriptor = {