Origin: ReproNim/containers repo where we were brave enough to start using v7 with unlocked files to avoid having symlinks for an image. TL;DR: here is command to replicate:

$> git clone --depth=50 http://github.com/repronim/containers && cd containers && git fetch origin +refs/pull/19/merge: && git checkout -qf 'HEAD^{}' && git branch && git fetch origin git-annex && git remote add --fetch datalad.datasets.org http://datasets.datalad.org/repronim/containers/.git && git annex upgrade && git annex get scripts/tests/ && ls -l scripts/tests/                                    
Cloning into 'containers'...                                                                                                                  
warning: redirecting to https://github.com/repronim/containers/
remote: Enumerating objects: 404, done.
remote: Counting objects: 100% (404/404), done.
remote: Compressing objects: 100% (208/208), done.
remote: Total 404 (delta 198), reused 367 (delta 171), pack-reused 0
Receiving objects: 100% (404/404), 59.13 KiB | 1.34 MiB/s, done.
Resolving deltas: 100% (198/198), done.
LICENSE  README.md  binds/  images/  scripts/
warning: redirecting to https://github.com/repronim/containers/
remote: Enumerating objects: 21, done.
remote: Counting objects: 100% (21/21), done.
remote: Compressing objects: 100% (10/10), done.
remote: Total 12 (delta 9), reused 4 (delta 2), pack-reused 0
Unpacking objects: 100% (12/12), done.
From http://github.com/repronim/containers
 * branch            refs/pull/19/merge -> FETCH_HEAD
* (HEAD detached at 44d55ad)
  master
warning: redirecting to https://github.com/repronim/containers/
remote: Enumerating objects: 798, done.
remote: Counting objects: 100% (798/798), done.
remote: Compressing objects: 100% (167/167), done.
remote: Total 795 (delta 423), reused 788 (delta 416), pack-reused 0
Receiving objects: 100% (795/795), 55.50 KiB | 1.50 MiB/s, done.
Resolving deltas: 100% (423/423), done.
From http://github.com/repronim/containers
 * branch            git-annex  -> FETCH_HEAD
Updating datalad.datasets.org
From http://datasets.datalad.org/repronim/containers/
 * [new branch]      git-annex     -> datalad.datasets.org/git-annex
 * [new branch]      master        -> datalad.datasets.org/master
 * [new branch]      synced/master -> datalad.datasets.org/synced/master
upgrade (merging datalad.datasets.org/git-annex into git-annex...)
(recording state in git...)
(v5 to v6...) (v6 to v7...) ok
(recording state in git...)
get scripts/tests/arg-test.simg 
  Remote origin not usable by git-annex; setting annex-ignore
(from datalad.datasets.org...) 
(checksum...) ok                  
(recording state in git...)
total 12
-rw------- 1 yoh yoh 259 Jul 11 16:10 Singularity.arg-test
-rw------- 1 yoh yoh  68 Jul 11 16:10 arg-test.simg
-rwx------ 1 yoh yoh 981 Jul 11 16:10 test_singularity_cmd.bats*

as you can see the arg-test.sim is only 68 bytes, not 2MB or a symlink.

fixed --Joey