It seems that a baseline test would need to:
Start on an image with android MNC
Create a new ecryptfs directory and install an android app
Update android image to NYC
migrate home directory to ext4-crypto
Verify that android app still launches

We could also write a test that just checks to make sure that files were copied correctly, but that currently has very good unit test coverage so the marginal benefit would be low.

Starting Android MNC is going to be very difficult on actual board, and going to be difficult to maintain.

How about maintaining a tarball of existing MNC data directory. (I imagine that would also be hard to maintain)
Keeping verification to the level of Android apps launching could also be flaky.

I guess these things should at least be verified in AU test (manual testing).

It would be nice if things can be automated, but I wouldn't try too hard if this turns out to be very difficult.

The archive should be able to work.
I'd be skeptical of anything that doesn't verify that the android app actually runs since the unit tests should cover everything below that.
I'm pretty sure we have a lot of other tests that verify various apps run, so this shouldn't be too crazy.

I believe dspaid started working on it.

any updates? 

Made good progress today.  I've got an autotest that sets up a pre-created ecryptfs home, migrates it, and verifies that android still boots and an app that was installed in the ecryptfs home still runs.  Next I need to clean up the code and set up the pre-created home as a proper autotest dependency before submission.

sounds good. 
I looked at writing a simple server test
https://chromium-review.googlesource.com/502768
but seems like doing anything involved needs to be split into client tests 
and also be able to use code like:

https://cs.corp.google.com/chromeos_public/src/third_party/autotest/files/client/cros/cryptohome.py?q=CryptohomeProxy&dr=CSs&l=411

The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/third_party/autotest/+/be9789ce5ecfccb15bba6a181a9f3e815ce04516

commit be9789ce5ecfccb15bba6a181a9f3e815ce04516
Author: Dan Spaid <dspaid@google.com>
Date: Mon May 22 12:02:46 2017

Add support for mount_ex and crypto-migration

Add relevent methods to support autotests dealing with direncryption
migration.

BUG= chromium:714474 
TEST=test_that kevin cheets_MigrationTest

Change-Id: I9c0e0020b3303472430e7f8d6d8289f1c85de668
Reviewed-on: https://chromium-review.googlesource.com/509370
Commit-Ready: Dan Spaid <dspaid@chromium.org>
Tested-by: Dan Spaid <dspaid@chromium.org>
Reviewed-by: Ryo Hashimoto <hashimoto@chromium.org>

[modify] https://crrev.com/be9789ce5ecfccb15bba6a181a9f3e815ce04516/client/cros/cryptohome.py

The following revision refers to this bug:
  https://chrome-internal.googlesource.com/chromeos/autotest-cheets/+/3a515f2f323418b47e8608052672c415caf20f00

commit 3a515f2f323418b47e8608052672c415caf20f00
Author: Dan Spaid <dspaid@google.com>
Date: Fri Jun 23 04:52:00 2017