add tests for attribute errors

test/static_analysis/attribute_error.py

@@ -0,0 +1,39 @@
+class Cls():
+    class_attr = ''
+    def __init__(self, input):
+        self.instance_attr = 3
+        self.input = input
+
+    def f(self):
+        #! attribute-error
+        return self.not_existing
+
+    def undefined_object(self, obj):
+        """
+        Uses an arbitrary object and performs an operation on it, shouldn't
+        be a problem.
+        """
+        obj.arbitrary_lookup
+
+    def defined_lookup(self, obj):
+        """
+        Uses an arbitrary object and performs an operation on it, shouldn't
+        be a problem.
+        """
+        obj.upper
+        #! attribute-error
+        obj.arbitrary_lookup
+
+    #! attribute-error
+    class_attr = a
+
+Cls().defined_lookup('')
+
+c = Cls()
+c.class_attr
+Cls.class_attr
+#! attribute-error
+Cls.class_attr_error
+c.instance_attr
+#! attribute-error
+c.instance_attr_error