Write a script to help validate a migration

Start with checking commit counts.

hg_git_validator.py

@@ -0,0 +1,27 @@
+import hg_git_migrator
+
+
+def check_commit_count(hg_path, git_path):
+    with hg_git_migrator.pushd(hg_path):
+        hg_results = hg_git_migrator.strict_execute('hg id --num --rev tip')
+    hg_count = int(hg_results.stdout) + 1
+    with hg_git_migrator.pushd(git_path):
+        git_results = hg_git_migrator.strict_execute('git log --pretty=oneline')
+    git_count = len(git_results.stdout.splitlines())
+    if hg_count != git_count:
+        raise ValueError('hg commit count != git commit count '
+                         '({} != {})'.format(hg_count, git_count))
+
+
+
+if __name__ == '__main__':
+    import argparse
+
+    parser = argparse.ArgumentParser()
+    parser.add_argument("hg_repo", help="location of mercurial repository in the filesystem.")
+    parser.add_argument("git_repo", help="location of git repository in the filesystem.")
+    args = parser.parse_args()
+
+    hg_git_migrator.check_prerequisites(hg_git_ext=False)
+
+    check_commit_count(args.hg_repo, args.git_repo)