Fix ansible-test merge change detection.

test/runner/lib/git.py

@@ -59,6 +59,24 @@ class Git(object):
         cmd = ['symbolic-ref', '--short', 'HEAD']
         return self.run_git(cmd).strip()
 
+    def get_rev_list(self, commits=None, max_count=None):
+        """
+        :type commits: list[str] | None
+        :type max_count: int | None
+        :rtype: list[str]
+        """
+        cmd = ['rev-list']
+
+        if commits:
+            cmd += commits
+        else:
+            cmd += ['HEAD']
+
+        if max_count:
+            cmd += ['--max-count', '%s' % max_count]
+
+        return self.run_git_split(cmd)
+
     def get_branch_fork_point(self, branch):
         """
         :type branch: str