Merge ~cjwatson/launchpad:py3-makePackageDiff-bytes into launchpad:master

[Colin Watson]

Fix makePackageDiff for Python 3

The diff content should be bytes, not text.

[Thiago F. Pappacena (pappacena)]

LGTM

review: Approve

diff --git a/lib/lp/testing/factory.py b/lib/lp/testing/factory.py
index b2cf34f..14e917d 100644
--- a/lib/lp/testing/factory.py
+++ b/lib/lp/testing/factory.py
@@ -4490,7 +4490,7 @@ class BareLaunchpadObjectFactory(ObjectFactory):
         if date_fulfilled is None:
             date_fulfilled = UTC_NOW
         if diff_content is None:
-            diff_content = self.getUniqueString("packagediff")
+            diff_content = self.getUniqueBytes("packagediff")
         lfa = self.makeLibraryFileAlias(
             filename=diff_filename, content=diff_content)
         return ProxyFactory(