test do
   assert_equal "zsh", shell_output("zsh -c '. #{opt_share}/kube-ps1.sh && echo $KUBE_PS1_SHELL'")
 end



$ brew test kube-ps1
Testing kube-ps1
==> zsh -c '. /usr/local/opt/kube-ps1/share/kube-ps1.sh && echo $KUBE_PS1_SHELL'
/usr/local/opt/kube-ps1/share/kube-ps1.sh:27: character not in range
Error: kube-ps1: failed
An exception occurred within a child process:
  Test::Unit::AssertionFailedError: <0> expected but was
<126>.
/Library/Ruby/Gems/2.3.0/gems/test-unit-3.1.5/lib/test/unit/assertions.rb:55:in `block in assert_block'
/Library/Ruby/Gems/2.3.0/gems/test-unit-3.1.5/lib/test/unit/assertions.rb:1632:in `_wrap_assertion'
/Library/Ruby/Gems/2.3.0/gems/test-unit-3.1.5/lib/test/unit/assertions.rb:53:in `assert_block'
/Library/Ruby/Gems/2.3.0/gems/test-unit-3.1.5/lib/test/unit/assertions.rb:240:in `assert_equal'
/usr/local/Homebrew/Library/Homebrew/formula_assertions.rb:10:in `shell_output'
/usr/local/Homebrew/Library/Taps/homebrew/homebrew-core/Formula/kube-ps1.rb:24:in `block in <class:KubePs1>'
/usr/local/Homebrew/Library/Homebrew/formula.rb:1724:in `block (3 levels) in run_test'
/usr/local/Homebrew/Library/Homebrew/utils.rb:476:in `with_env'
/usr/local/Homebrew/Library/Homebrew/formula.rb:1723:in `block (2 levels) in run_test'
/usr/local/Homebrew/Library/Homebrew/formula.rb:864:in `with_logging'
/usr/local/Homebrew/Library/Homebrew/formula.rb:1722:in `block in run_test'
/usr/local/Homebrew/Library/Homebrew/formula.rb:1961:in `block in mktemp'
/usr/local/Homebrew/Library/Homebrew/mktemp.rb:55:in `block in run'
/usr/local/Homebrew/Library/Homebrew/mktemp.rb:55:in `chdir'
/usr/local/Homebrew/Library/Homebrew/mktemp.rb:55:in `run'
/usr/local/Homebrew/Library/Homebrew/formula.rb:1960:in `mktemp'
/usr/local/Homebrew/Library/Homebrew/formula.rb:1716:in `run_test'
/usr/local/Homebrew/Library/Homebrew/test.rb:28:in `block in <main>'
/System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/ruby/2.3.0/timeout.rb:91:in `block in timeout'
/System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/ruby/2.3.0/timeout.rb:33:in `block in catch'
/System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/ruby/2.3.0/timeout.rb:33:in `catch'
/System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/ruby/2.3.0/timeout.rb:33:in `catch'
/System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/ruby/2.3.0/timeout.rb:106:in `timeout'
/usr/local/Homebrew/Library/Homebrew/test.rb:27:in `<main>'


##########################################################

Line 27:

KUBE_PS1_SYMBOL_DEFAULT=${KUBE_PS1_SYMBOL_DEFAULT:-$'\u2388 '}