diff --git a/lib/model.js b/lib/model.js
index cf214bd1..1c6457db 100644
--- a/lib/model.js
+++ b/lib/model.js
@@ -444,7 +444,9 @@ AbstractClass.destroyAll = function destroyAll(cb) {
     if (stillConnecting(this.schema, this, arguments)) return;
 
     this.schema.adapter.destroyAll(this.modelName, function (err) {
-        cb(err);
+        if ('function' === typeof cb) {
+            cb(err);
+        }
     }.bind(this));
 };
 
diff --git a/lib/schema.js b/lib/schema.js
index 0ea107d8..96205f93 100644
--- a/lib/schema.js
+++ b/lib/schema.js
@@ -176,6 +176,7 @@ Schema.prototype.define = function defineClass(className, properties, settings)
     if (args.length == 1) properties = {}, args.push(properties);
     if (args.length == 2) settings   = {}, args.push(settings);
 
+    properties = properties || {};
     settings = settings || {};
 
     // every class can receive hash of data as optional param
diff --git a/test/relations.test.js b/test/relations.test.js
index 9d88a1d4..ef7c63cf 100644
--- a/test/relations.test.js
+++ b/test/relations.test.js
@@ -183,8 +183,8 @@ describe('relations', function() {
                     t.should.be.an.instanceOf(Tag);
                     ArticleTag.findOne(function(e, at) {
                         should.exist(at);
-                        at.tagId.should.equal(t.id);
-                        at.articleId.should.equal(article.id);
+                        at.tagId.toString().should.equal(t.id.toString());
+                        at.articleId.toString().should.equal(article.id.toString());
                         done();
                     });
                 });
@@ -220,7 +220,8 @@ describe('relations', function() {
             Article.findOne(function(e, article) {
                 article.tags(function(e, tags) {
                     var len = tags.length;
-                    article.tags.remove(tags[0], function(e, at) {
+                    tags.should.not.be.empty;
+                    article.tags.remove(tags[0], function(e) {
                         should.not.exist(e);
                         article.tags(true, function(e, tags) {
                             tags.should.have.lengthOf(len - 1);