added a simple test for search_cpp
diff --git a/Lib/distutils/command/config.py b/Lib/distutils/command/config.py
index 74eed78..43a8dc8 100644
--- a/Lib/distutils/command/config.py
+++ b/Lib/distutils/command/config.py
@@ -202,11 +202,10 @@
         preprocesses an empty file -- which can be useful to determine the
         symbols the preprocessor and compiler set by default.
         """
-
         self._check_compiler()
-        (src, out) = self._preprocess(body, headers, include_dirs, lang)
+        src, out = self._preprocess(body, headers, include_dirs, lang)
 
-        if type(pattern) is StringType:
+        if isinstance(pattern, str):
             pattern = re.compile(pattern)
 
         file = open(out)