Extend test for infinite recursion bug in find_non_copyable_vars (#71)

These tests are still disabled as they are is still failing, but they now
clearly show the problem.

Author: iMichka

unittests/data/test_stream.hpp

@@ -5,6 +5,40 @@
 
 #include <sstream>
 
+// Demonstration of the real problem with basic c++
+namespace Test1 {
+
+// Forward declaration
+class Base2;
+
+// Base 1, with pointer to Base2
+class Base1 {
+  private:
+    Base1();
+
+  protected:
+    Base2* aBasePtr2;
+};
+
+// Base 2, child class of Base1
+class Base2: public Base1 {
+  private:
+    Base2();
+};
+
+// Child class of Base2
+// Holds a pointer to Base2
+class Child: public Base2 {
+  private:
+    Child();
+
+  protected:
+    Base2* aBasePtr2;
+};
+
+}
+
+// Real-life test with std::istream where this happened
 namespace Test2 {
 
 class FileStreamDataStream {

unittests/test_stream.py

@@ -17,23 +17,52 @@ def __init__(self, *args):
         self.header = "test_stream.hpp"
         self.config.cflags = "-std=c++11"
 
-    def test_stream_non_copyable(self):
+    def test_infinite_recursion_base_classes(self):
         """
         Test find_noncopyable_vars
 
         See #71
 
-        find_noncopyable_vars is throwing:
+        find_noncopyable_vars was throwing:
         RuntimeError: maximum recursion depth exceeded while
         calling a Python object
         """
         decls = parser.parse([self.header], self.config)
         global_ns = declarations.get_global_namespace(decls)
 
+        # Description of the problem (before the fix):
+        # find_noncopyable_vars (on Child class) looks up the variables,
+        # and finds aBasePtr2 (a pointer to the Base2 class).
+        # Then it looks recursively at the base classes of Base2, and finds
+        # Base1. Then, it looks up the variables from Base, to check if Base1
+        # is non copyable. It finds another aBasePtr2 variable, which leads to
+        # a new check of Base2; this recurses infinitely.
+        test_ns = global_ns.namespace('Test1')
+        cls = test_ns.class_('Child')
+        declarations.type_traits_classes.find_noncopyable_vars(cls)
+
+    def test_infinite_recursion_sstream(self):
+        """
+        Test find_noncopyable_vars
+
+        See #71
+
+        find_noncopyable_vars was throwing:
+        RuntimeError: maximum recursion depth exceeded while
+        calling a Python object
+        """
+        decls = parser.parse([self.header], self.config)
+        global_ns = declarations.get_global_namespace(decls)
+
+        # Real life example of the bug. This leads to a similar error,
+        # but the situation is more complex as there are multiple
+        # classes that are related the one to the others
+        # (basic_istream, basic_ios, ios_base, ...)
         test_ns = global_ns.namespace('Test2')
         cls = test_ns.class_('FileStreamDataStream')
         declarations.type_traits_classes.find_noncopyable_vars(cls)
 
+
 def create_suite():
     suite = unittest.TestSuite()
     suite.addTest(unittest.makeSuite(Test))