Bug #1430076 fix installing when extras is not installed.

Change-Id: Icc9c40d6ef74e6b12323fdab7ce0581ec68794b7

NEWS

@@ -7,6 +7,16 @@ Changes and improvements to testtools_, grouped by release.
 NEXT
 ~~~~
 
+1.6.1
+~~~~~
+
+Changes
+-------
+
+* Fix installing when ``extras`` is not already installed. Our guards
+  for the absence of unittest2 were not sufficient.
+  (Robert Collins, #1430076)
+
 1.6.0
 ~~~~~
 

testtools/__init__.py

@@ -122,4 +122,4 @@ else:
 # If the releaselevel is 'final', then the tarball will be major.minor.micro.
 # Otherwise it is major.minor.micro~$(revno).
 
-__version__ = (1, 7, 0, 'dev', 0)
+__version__ = (1, 6, 1, 'final', 0)

testtools/run.py

@@ -25,7 +25,10 @@ from testtools.testsuite import filter_by_ids, iterate_tests, sorted_tests
 defaultTestLoader = unittest.defaultTestLoader
 defaultTestLoaderCls = unittest.TestLoader
 have_discover = True
-discover_impl = unittest.loader
+# This shouldn't really be public - its legacy.  Try to set it if we can, and
+# if we can't (during installs before unittest2 is installed) just stub it out
+# to None.
+discover_impl = getattr(unittest, 'loader', None)
 
 # Kept for API compatibility, but no longer used.
 BUFFEROUTPUT = ""