caucase.test: Fix testWSGI on python3.

wsgi.input is specified to be a bytes object, not a string object.

caucase/test.py

@@ -1860,7 +1860,7 @@ class CaucaseTest(unittest.TestCase):
     self.assertEqual(request({
       'PATH_INFO': '/cau/csr',
       'REQUEST_METHOD': 'PUT',
-      'wsgi.input': StringIO(),
+      'wsgi.input': BytesIO(),
     })[0], 500)
     self.assertEqual(request({
       'PATH_INFO': '/cau/csr',
@@ -1897,50 +1897,50 @@ class CaucaseTest(unittest.TestCase):
       'REQUEST_METHOD': 'PUT',
       'CONTENT_TYPE': 'application/json',
       'CONTENT_LENGTH': 'a',
-      'wsgi.input': StringIO(),
+      'wsgi.input': BytesIO(),
     })[0], 400)
     self.assertEqual(request({
       'PATH_INFO': '/cau/crt/renew',
       'REQUEST_METHOD': 'PUT',
       'CONTENT_TYPE': 'application/json',
       'CONTENT_LENGTH': str(wsgi.MAX_BODY_LENGTH + 1),
-      'wsgi.input': StringIO(),
+      'wsgi.input': BytesIO(),
     })[0], 413)
     self.assertEqual(request({
       'PATH_INFO': '/cau/crt/renew',
       'REQUEST_METHOD': 'PUT',
       'CONTENT_TYPE': 'application/json',
-      'wsgi.input': StringIO(u'{'),
+      'wsgi.input': BytesIO(b'{'),
     })[0], 400)
     self.assertEqual(request({
       'PATH_INFO': '/cau/crt/revoke',
       'REQUEST_METHOD': 'PUT',
       'CONTENT_TYPE': 'application/json',
-      'wsgi.input': StringIO(u'{"digest": null}'),
+      'wsgi.input': BytesIO(b'{"digest": null}'),
     })[0], UNAUTHORISED_STATUS)
     self.assertEqual(request({
       'PATH_INFO': '/cau/crt/revoke',
       'REQUEST_METHOD': 'PUT',
       'CONTENT_TYPE': 'application/json',
-      'wsgi.input': StringIO(u'{"digest":"sha256","payload":""}'),
+      'wsgi.input': BytesIO(b'{"digest":"sha256","payload":""}'),
     })[0], 400)
     self.assertEqual(request({
       'PATH_INFO': '/cau/crt/a',
       'REQUEST_METHOD': 'PUT',
       'CONTENT_TYPE': 'text/plain',
-      'wsgi.input': StringIO(u''),
+      'wsgi.input': BytesIO(b''),
     })[0], 400)
     self.assertEqual(request({
       'PATH_INFO': '/cau/crt/123',
       'REQUEST_METHOD': 'PUT',
       'CONTENT_TYPE': 'text/plain',
-      'wsgi.input': StringIO(u''),
+      'wsgi.input': BytesIO(b''),
     })[0], UNAUTHORISED_STATUS)
     self.assertEqual(request({
       'PATH_INFO': '/cau/crt/123',
       'REQUEST_METHOD': 'PUT',
       'CONTENT_TYPE': 'text/plain',
-      'wsgi.input': StringIO(u'foo'),
+      'wsgi.input': BytesIO(b'foo'),
     })[0], 400)
     self.assertEqual(request({
       'PATH_INFO': '/cau/crt/123',
@@ -2125,7 +2125,7 @@ class CaucaseTest(unittest.TestCase):
         'PATH_INFO': '/cors',
         'REQUEST_METHOD': 'POST',
         'CONTENT_TYPE': 'application/x-www-form-urlencoded',
-        'wsgi.input': StringIO(utils.toUnicode(urlencode(input_dict))),
+        'wsgi.input': BytesIO(urlencode(input_dict).encode('ascii')),
       }
       base_request_reader_dict.update(kw)
       return base_request_reader_dict