added tests, pep8 format

test/test_persistence.py

@@ -5,6 +5,7 @@ from dataset import connect
 from dataset.util import DatasetException
 from sample_data import TEST_DATA
 
+
 class DatabaseTestCase(unittest.TestCase):
 
     def setUp(self):
@@ -113,7 +114,25 @@ class TableTestCase(unittest.TestCase):
         else:
             assert False, 'we should not reach else block, no exception raised!'
 
+    def test_columns(self):
+        cols = self.tbl.columns
+        assert isinstance(cols, set), 'columns should be a set'
+        assert len(cols) == 4, 'column count mismatch'
+        assert 'date' in cols and 'temperature' in cols and 'place' in cols
+
+    def test_iter(self):
+        c = 0
+        for row in self.tbl:
+            c += 1
+        assert c == len(self.tbl)
+
+    def test_update(self):
+        self.tbl.upsert({
+            'date': datetime(2011, 01, 02),
+            'temperature': -10,
+            'place': 'Berlin'},
+            ['place']
+        )
 
 if __name__ == '__main__':
     unittest.main()
-