1 files changed, 101 insertions, 0 deletions
diff --git a/tests/functional/n/non/non_iterator_returned.py b/tests/functional/n/non/non_iterator_returned.py
new file mode 100644
index 000000000..4d0dd2a39
--- /dev/null
+++ b/tests/functional/n/non/non_iterator_returned.py
@@ -0,0 +1,101 @@
+"""Check non-iterators returned by __iter__ """
+
+# pylint: disable=too-few-public-methods, missing-docstring, no-self-use, useless-object-inheritance, consider-using-with
+
+
+class FirstGoodIterator(object):
+    """ yields in iterator. """
+
+    def __iter__(self):
+        for index in range(10):
+            yield index
+
+
+class SecondGoodIterator(object):
+    """ __iter__ and next """
+
+    def __iter__(self):
+        return self
+
+    def __next__(self):
+        """ Infinite iterator, but still an iterator """
+        return 1
+
+    def next(self):
+        """Same as __next__, but for Python 2."""
+        return 1
+
+
+class ThirdGoodIterator(object):
+    """ Returns other iterator, not the current instance """
+
+    def __iter__(self):
+        return SecondGoodIterator()
+
+
+class FourthGoodIterator(object):
+    """ __iter__ returns iter(...) """
+
+    def __iter__(self):
+        return iter(range(10))
+
+
+class IteratorMetaclass(type):
+    def __next__(cls):
+        return 1
+
+    def next(cls):
+        return 2
+
+
+class IteratorClass(object, metaclass=IteratorMetaclass):
+    """Iterable through the metaclass."""
+
+
+class FifthGoodIterator(object):
+    """__iter__ returns a class which uses an iterator-metaclass."""
+
+    def __iter__(self):
+        return IteratorClass
+
+
+class FileBasedIterator(object):
+    def __init__(self, path):
+        self.path = path
+        self.file = None
+
+    def __iter__(self):
+        if self.file is not None:
+            self.file.close()
+        self.file = open(self.path, encoding="utf-8")
+        # self file has two infered values: None and <instance of 'file'>
+        # we don't want to emit error in this case
+        return self.file
+
+
+class FirstBadIterator(object):
+    """ __iter__ returns a list """
+
+    def __iter__(self):  # [non-iterator-returned]
+        return []
+
+
+class SecondBadIterator(object):
+    """ __iter__ without next """
+
+    def __iter__(self):  # [non-iterator-returned]
+        return self
+
+
+class ThirdBadIterator(object):
+    """ __iter__ returns an instance of another non-iterator """
+
+    def __iter__(self):  # [non-iterator-returned]
+        return SecondBadIterator()
+
+
+class FourthBadIterator(object):
+    """__iter__ returns a class."""
+
+    def __iter__(self):  # [non-iterator-returned]
+        return ThirdBadIterator