Failed to parse/validate config: Testing* options may only be changed in testing Tor networks!
$ src/or/tor -f /tmp/empty
May 28 16:03:10.037 [notice] Tor v0.2.5.0-alpha-dev (git-d3125a3e404f4967) running on Linux with Libevent 2.0.19-stable and OpenSSL 1.0.1e.
May 28 16:03:10.037 [notice] Tor can't help you if you use it wrong! Learn how to be safe at https://www.torproject.org/download/download#warning
May 28 16:03:10.037 [notice] This version is not a stable Tor release. Expect more bugs than usual.
May 28 16:03:10.037 [notice] Read configuration file "/tmp/empty".
May 28 16:03:10.044 [warn] Failed to parse/validate config: Testing* options may only be changed in testing Tor networks!
May 28 16:03:10.044 [err] Reading config failed--see warnings above.
It looks like commit b0d4ca49 makes Tor unable to start.