Try to fix test_web.py on Python 2.

src/allmydata/test/common_web.py

@@ -48,10 +48,10 @@ class VerboseError(Error):
 @inlineCallbacks
 def do_http(method, url, **kwargs):
     """
-    Run HTTP query, return Deferred of body as Unicode.
+    Run HTTP query, return Deferred of body as bytes.
     """
     response = yield treq.request(method, url, persistent=False, **kwargs)
-    body = yield treq.text_content(response, "utf-8")
+    body = yield treq.content(response)
     # TODO: replace this with response.fail_for_status when
     # https://github.com/twisted/treq/pull/159 has landed
     if 400 <= response.code < 600:

src/allmydata/test/test_system.py

@@ -55,7 +55,7 @@ from .common import (
     TEST_RSA_KEY_SIZE,
     SameProcessStreamEndpointAssigner,
 )
-from .common_web import do_http, Error
+from .common_web import do_http as do_http_bytes, Error
 from .web.common import (
     assert_soup_has_tag_with_attributes
 )
@@ -78,6 +78,11 @@ def run_cli(*args, **kwargs):
         ensure_text(args[0]), [ensure_text(a) for a in args[1:]], **kwargs)
 
 
+def do_http(*args, **kwargs):
+    """Wrapper for do_http() that returns Unicode."""
+    return do_http_bytes(*args, **kwargs).addCallback(
+        lambda b: str(b, "utf-8"))
+
 
 LARGE_DATA = b"""
 This is some data to publish to the remote grid.., which needs to be large