Capture stdout in for test_wsgi:test_debug

This adds stdout capture, and verification for the wsgi.Debug
middleware test. It was previously untested, and spewed stdout into
the test output stream.

Change-Id: I564d04c7d39df8bf0ee02486c4bb47161fc241c1

nova/tests/unit/api/test_wsgi.py

@@ -19,7 +19,9 @@
 Test WSGI basics and provide some helper functions for other WSGI tests.
 """
 
+import fixtures
 import routes
+from six.moves import StringIO
 import webob
 
 from nova import test
@@ -29,6 +31,11 @@ from nova import wsgi
 class Test(test.NoDBTestCase):
 
     def test_debug(self):
+        """This tests optional middleware we have which dumps
+        the requests to stdout.
+        """
+        self.output = StringIO()
+        self.useFixture(fixtures.MonkeyPatch('sys.stdout', self.output))
 
         class Application(wsgi.Application):
             """Dummy application to test debug."""
@@ -40,6 +47,9 @@ class Test(test.NoDBTestCase):
         application = wsgi.Debug(Application())
         result = webob.Request.blank('/').get_response(application)
         self.assertEqual(result.body, b"Test result")
+        self.assertIn(
+            '**************************************** REQUEST ENVIRON',
+            self.output.getvalue())
 
     def test_router(self):