Converting various classes to namedtuples

appengine/findit/crash/test/stacktrace_test.py

Index: appengine/findit/crash/test/stacktrace_test.py
diff --git a/appengine/findit/crash/test/stacktrace_test.py b/appengine/findit/crash/test/stacktrace_test.py
index e6955a9a3e4bc743e11a235299389bf7d49c37ec..f0a5ace6fa66b612615efa5205101f5f3da021bb 100644
--- a/appengine/findit/crash/test/stacktrace_test.py
+++ b/appengine/findit/crash/test/stacktrace_test.py
@@ -27,10 +27,10 @@ class CallStackTest(StacktraceTestSuite):
     frame = StackFrame(0, 'src/', 'func', 'f.cc', 'src/f.cc', [])
     self.assertEqual(frame.BlameUrl('1'), None)
 
-    frame.repo_url = 'https://repo_url'
+    frame = frame._replace(repo_url = 'https://repo_url')
     self.assertEqual(frame.BlameUrl('1'), 'https://repo_url/+blame/1/f.cc')
 
-    frame.crashed_line_numbers = [9, 10]
+    frame = frame._replace(crashed_line_numbers = [9, 10])

[Sharu Jiang, 2016/11/21 23:31:57]

Instead of changing fields of frame afterward, we can create new frames, since
they are namedtuples right now :)

[wrengr, 2016/11/22 18:33:40]

Sure. Using ``_replace`` just means all the other fields of the new namedtuple
will be inherited form the old one; so we don't have to repeat 'func', 'f.cc',
etc

     self.assertEqual(frame.BlameUrl('1'), 'https://repo_url/+blame/1/f.cc#9')
 
   def testFrameListInitCallStack(self):