diff --git a/src/allmydata/test/test_checker.py b/src/allmydata/test/test_checker.py
index 936d270ae..a7042468a 100644
--- a/src/allmydata/test/test_checker.py
+++ b/src/allmydata/test/test_checker.py
@@ -173,7 +173,7 @@ class WebResultsRendering(unittest.TestCase):
         return c
 
     def render_json(self, resource):
-        return self.successResultOf(render(resource, {"output": ["json"]}))
+        return self.successResultOf(render(resource, {b"output": [b"json"]}))
 
     def render_element(self, element, args=None):
         if args is None:
@@ -186,7 +186,7 @@ class WebResultsRendering(unittest.TestCase):
         html = self.render_element(lcr)
         self.failUnlessIn(b"Literal files are always healthy", html)
 
-        html = self.render_element(lcr, args={"return_to": ["FOOURL"]})
+        html = self.render_element(lcr, args={b"return_to": [b"FOOURL"]})
         self.failUnlessIn(b"Literal files are always healthy", html)
         self.failUnlessIn(b'<a href="FOOURL">Return to file.</a>', html)
 
@@ -269,7 +269,7 @@ class WebResultsRendering(unittest.TestCase):
         self.failUnlessIn("File Check Results for SI=2k6avp", s) # abbreviated
         self.failUnlessIn("Not Recoverable! : rather dead", s)
 
-        html = self.render_element(w, args={"return_to": ["FOOURL"]})
+        html = self.render_element(w, args={b"return_to": [b"FOOURL"]})
         self.failUnlessIn(b'<a href="FOOURL">Return to file/directory.</a>',
                           html)