Add tests for has_changes

tests/functions/test_has_changes.py

@@ -0,0 +1,24 @@
+import sqlalchemy as sa
+from sqlalchemy.ext.declarative import declarative_base
+
+from sqlalchemy_utils import has_changes
+
+
+class TestHasChanges(object):
+    def setup_method(self, method):
+        Base = declarative_base()
+
+        class Article(Base):
+            __tablename__ = 'article_translation'
+            id = sa.Column(sa.Integer, primary_key=True)
+            title = sa.Column(sa.String(100))
+
+        self.Article = Article
+
+    def test_without_changed_attr(self):
+        article = self.Article()
+        assert not has_changes(article, 'title')
+
+    def test_with_changed_attr(self):
+        article = self.Article(title='Some title')
+        assert has_changes(article, 'title')