Replay: add check_replay_branch.py to check for EKF output changes

Create a replay log using master branch.
Check out a specified branch, compile and run Replay against replay log
Run check_replay.py over the produced log

Tools/Replay/check_replay_branch.py

@@ -0,0 +1,80 @@
+#!/usr/bin/env python
+
+'''
+Create a replay log using master branch.
+Check out a specified branch, compile and run Replay against replay log
+Run check_replay.py over the produced log
+'''
+
+import git
+import os
+import subprocess
+import sys
+
+import check_replay
+
+class CheckReplayBranch(object):
+    def __init__(self, master='remotes/origin/master'):
+        self.master = master
+
+    def find_topdir(self):
+        here = os.getcwd()
+        bits = here.split(os.path.sep)
+        while len(bits):
+#            print("bits: %s" % str(bits))
+            tmp = bits[:]
+            tmp.extend([".git"])  # can we look for something more specific?
+            flagfile = os.path.sep.join(tmp)
+            if os.path.exists(flagfile):
+#                print("Found in (%s)" % str(flagfile))
+                return os.path.sep.join(bits)
+            bits = bits[:-2]
+        raise FileNotFoundError()
+
+    def find_repo(self):
+        return git.Repo(self.topdir)
+
+    def assert_tree_clean(self):
+        if self.repo.is_dirty():
+            raise ValueError("Tree is dirty")
+
+    def run(self):
+        self.topdir = self.find_topdir()
+        self.repo = self.find_repo()
+        self.assert_tree_clean()
+
+        # remember where we were:
+        old_branch = self.repo.active_branch
+
+        # check out the master branch:
+        self.repo.head.reference = self.master
+        self.repo.head.reset(index=True, working_tree=True)
+
+        # generate a log:
+        os.chdir(self.topdir)
+        print("chdir (%s)" % str(self.topdir))
+        subprocess.check_call(["Tools/autotest/autotest.py", "--debug", "build.Copter", "test.Copter.Replay"])
+
+        logfile_name = "00000004.BIN"  # FIXME; parse output of subprocess?
+        logfile_path = os.path.join("logs", logfile_name)
+
+        # check out the original branch:
+        self.repo.head.reference = old_branch
+        self.repo.head.reset(index=True, working_tree=True)
+
+        # run check_replay across Replay log
+        return check_replay.check_log(logfile_path)
+
+if __name__ == '__main__':
+    import sys
+    from argparse import ArgumentParser
+    parser = ArgumentParser(description=__doc__)
+    parser.add_argument("--master", default='remotes/origin/master', help="branch to consider master branch")
+
+    args = parser.parse_args()
+
+    s = CheckReplayBranch(master=args.master)
+    if not s.run():
+        sys.exit(1)
+
+    sys.exit(0)