fix #429 Multiple Models can't mixin same class

Signed-off-by: Clark Wang <clark.wangs@gmail.com>

lib/jutil.js

@@ -1,4 +1,5 @@
 var util = require('util');
+var _ = require('lodash');
 /**
  *
  * @param newClass
@@ -75,11 +76,12 @@ function mixInto(sourceScope, targetScope, options) {
     var isDelegate = isFunc && targetProperty.value._delegate;
     var shouldOverride = options.override || !targetPropertyExists || isDelegate;
 
-    if (shouldOverride) {
+    if (propertyName == '_mixins') {
-      if (sourceIsFunc) {
+      targetScope._mixins = _.union(targetScope._mixins, sourceScope._mixins);
-        sourceProperty.value = sourceProperty.value;
+      return;
-      }
+    }
 
+    if (shouldOverride) {
       Object.defineProperty(targetScope, propertyName, sourceProperty);
     }
   });

test/mixins.test.js

@@ -105,4 +105,36 @@ describe('Model class', function () {
     });
   });
 
+  describe('#mixin()', function () {
+
+    var Person, Author, Address;
+
+    beforeEach(function () {
+      Address = modelBuilder.define('Address', {
+        street: { type: 'string', required: true },
+        city: { type: 'string', required: true }
+      });
+      var memory = new DataSource('mem', {connector: Memory}, modelBuilder);
+      Person = memory.createModel('Person', { name: 'string' });
+      Author = memory.createModel('Author', { name: 'string' });
+    });
+
+    it('should register mixin class into _mixins', function () {
+      Person.mixin(Address);
+      Person._mixins.should.containEql(Address);
+    });
+
+    it('should NOT share mixins registry', function () {
+      Person.mixin(Address);
+      Author._mixins.should.not.containEql(Address);
+    });
+
+    it('should able to mixin same class', function () {
+      Person.mixin(Address);
+      Author.mixin(Address);
+      Author._mixins.should.containEql(Address);
+    });
+
+  });
+
 });