Fixed parsers.Native reset (#83)

tabulator/parsers/native.py

@@ -4,6 +4,7 @@
 from __future__ import absolute_import
 from __future__ import unicode_literals
 
+import six
 from .. import exceptions
 from . import api
 
@@ -26,6 +27,9 @@ def closed(self):
         return True
 
     def open(self, source, encoding, loader):
+        if hasattr(source, '__next__' if six.PY3 else 'next'):
+            message = 'Only callable returning an iterator is supported'
+            raise exceptions.ParsingError(message)
         self.close()
         self.__source = source
         self.reset()
@@ -44,6 +48,8 @@ def extended_rows(self):
 
     def __iter_extended_rows(self):
         items = self.__source
+        if not hasattr(items, '__iter__'):
+            items = items()
         for number, item in enumerate(items, start=1):
             if isinstance(item, (tuple, list)):
                 yield (number, None, list(item))

tests/test_topen.py

@@ -212,15 +212,27 @@ def test_native_iterator():
     assert table.read() == [['id', 'name'], ['1', 'english'], ['2', '中国人']]
 
 
+def test_native_iterator():
+
+    # Get table
+    def generator():
+        yield ['id', 'name']
+        yield ['1', 'english']
+        yield ['2', '中国人']
+    with pytest.raises(exceptions.ParsingError) as excinfo:
+        iterator = generator()
+        topen(iterator)
+    assert 'callable' in str(excinfo.value)
+
+
 def test_native_generator():
 
     # Get table
     def generator():
         yield ['id', 'name']
         yield ['1', 'english']
         yield ['2', '中国人']
-    source = generator()
-    table = topen(source)
+    table = topen(generator)
 
     # Make assertions
     assert table.headers is None
@@ -433,6 +445,26 @@ def test_reset_and_sample_size():
         (7, ['id', 'name'], ['6', 'f'])]
 
 
+def test_reset_generator():
+
+    # Generator
+    def generator():
+        yield [1]
+        yield [2]
+
+    # Get table
+    table = topen(generator, sample_size=0)
+
+    # Make assertions
+    assert table.read() == [[1], [2]]
+
+    # Reset
+    table.reset()
+
+    # Make assertions
+    assert table.read() == [[1], [2]]
+
+
 # Tests [processors]
 
 def test_processors_headers():