After landing #367 and rebasing #477 onto it, I got a host of shellcheck warnings for the new run =<N> syntax along the lines of:

  run =0   true
      ^-- SC2283: Remove spaces around = to assign (or use [ ] to compare, or quote '=' if literal).

My decision to use = was that it is concise and I wanted to avoid run '=0'. However, seeing this warning made me acutely aware of the ramifications. Missing the space would assign run=0 and works without error because the next part is a command that should be runnable.

I see following ways going forward:

1. expect run '=0'
2. find another syntax for the return code check (I checked run ?0 and run ==0, which also give shellcheck warnings but at least would not fail silently when omitting the space)
3. stay with run =0 and update shellcheck to balk at run=0 and don't balk at run =0 in bats tests

Pinging @edsantiago since you floated other ideas in the original PR.

I am giving this some urgency since I want to settle the issue before run =<N> gets published in the next release.