1 files changed, 59 insertions, 0 deletions
diff --git a/pylint/test/functional/mapping_context.py b/pylint/test/functional/mapping_context.py
new file mode 100644
index 0000000..cfab8dc
--- /dev/null
+++ b/pylint/test/functional/mapping_context.py
@@ -0,0 +1,59 @@
+"""
+Checks that only valid values are used in a mapping context.
+"""
+# pylint: disable=missing-docstring,invalid-name,too-few-public-methods,no-self-use,import-error
+from __future__ import print_function
+
+
+def test(**kwargs):
+    print(kwargs)
+
+
+# dictionary value/comprehension
+dict_value = dict(a=1, b=2, c=3)
+dict_comp = {chr(x): x for x in range(256)}
+test(**dict_value)
+test(**dict_comp)
+
+
+# in order to be used in kwargs custom mapping class should define
+# __iter__(), __getitem__(key) and keys().
+class CustomMapping(object):
+    def __init__(self):
+        self.data = dict(a=1, b=2, c=3, d=4, e=5)
+
+    def __getitem__(self, key):
+        return self.data[key]
+
+    def keys(self):
+        return self.data.keys()
+
+test(**CustomMapping())
+test(**CustomMapping)  # [not-a-mapping]
+
+class NotMapping(object):
+    pass
+
+test(**NotMapping())  # [not-a-mapping]
+
+# skip checks if statement is inside mixin class
+class SomeMixin(object):
+    kwargs = None
+
+    def get_kwargs(self):
+        return self.kwargs
+
+    def run(self, **kwargs):
+        print(kwargs)
+
+    def dispatch(self):
+        kws = self.get_kwargs()
+        self.run(**kws)
+
+# skip uninferable instances
+from some_missing_module import Mapping
+
+class MyClass(Mapping):
+    pass
+
+test(**MyClass())