No idea, can't reproduce in any non-interactive environment. Maybe explicitly pipe nothing into it?
By the way, it's a rather shitty test anyway; it is actually testing Zsh's compinit, rather than zsh-completions, and it relies on the formula being linked. How about replacing it with something like
```rb
test do
(testpath/"test.zsh").write <<-EOS.undent
fpath=(#{pkgshare} $fpath)
autoload _ack
which _ack
EOS
assert_match /^_ack/, shell_output("/bin/zsh test.zsh")
end
```
Not saying this is any better, but it is basically functionally equivalent, and the shell doesn't need to be interactive (due to skipping `compinit` and directly autoloading `_ack`, which is the only thing `compinit` does that's relevant to `which _ack`).
I guess you can add these entries to `matrix.include`:
```yml
- os: linux
dist: trusty
env: USE_DOCKER=1 OS_TYPE=centos OS_VERSION=7
- os: linux
dist: trusty
env: USE_DOCKER=1 OS_TYPE=fedora OS_VERSION=24
```
etc. then test for `USE_DOCKER` in scripts.
For sanity and easier access to shell language syntax, including Bashism, I would put `before_install`, `script` and `after_success` into standalone scripts in a directory like `ci/`.
imagemagick@6 6.9.8-5
=====================
Created with `brew bump-formula-pr`.
---
Please remember to
```
brew mirror imagemagick@6
```
when merging.
Oh, I see you were talking about pkg-config. Sure, using pkg-config in Makefile shouldn't be a problem on macOS with any configuration: with or without pkg-config, with stock ncurses 5.x or third-party ncurses 6.x.