Since bug 699751 landed, we've been seeing this failure on our Windows test boxes on Thunderbird builds: TEST-UNEXPECTED-FAIL | e:/buildbot/comm-central-win32-opt-unittest-xpcshell/build/xpcshell/tests/toolkit/components/places/tests/migration/test_current_from_v10.js | 0 == 6 - See following stack: JS frame :: e:\buildbot\comm-central-win32-opt-unittest-xpcshell\build\xpcshell\head.js :: do_throw :: line 462 JS frame :: e:\buildbot\comm-central-win32-opt-unittest-xpcshell\build\xpcshell\head.js :: _do_check_eq :: line 556 JS frame :: e:\buildbot\comm-central-win32-opt-unittest-xpcshell\build\xpcshell\head.js :: do_check_eq :: line 577 JS frame :: e:/buildbot/comm-central-win32-opt-unittest-xpcshell/build/xpcshell/tests/toolkit/components/places/tests/migration/test_current_from_v10.js :: test_moz_hosts :: line 304 JS frame :: e:\buildbot\comm-central-win32-opt-unittest-xpcshell\build\xpcshell\head.js :: _run_next_test :: line 882 JS frame :: e:\buildbot\comm-central-win32-opt-unittest-xpcshell\build\xpcshell\head.js :: <TOP_LEVEL> :: line 429 These are opt builds running on VMs, so could there be a timing issue processing the sql statement?

yeah, it's possible we are not waiting for something. I'll look into it.

The problem is that moz_hosts is populated asynchronously but we check it synchronously, will fix this in bug 720258 since I have to add some test there.

fixed by bug 720258