exenv: test added

Closes Homebrew/legacy-homebrew#40013.

Signed-off-by: Dominyk Tiller <dominyktiller@gmail.com>

Formula/exenv.rb

@@ -1,23 +1,25 @@
-require 'formula'
-
 class Exenv < Formula
-  homepage 'https://github.com/mururu/exenv'
-  url 'https://github.com/mururu/exenv/archive/v0.1.0.tar.gz'
-  sha1 '0984b6c260e42d750c8df68c8f48c19a90dc5db9'
+  homepage "https://github.com/mururu/exenv"
+  url "https://github.com/mururu/exenv/archive/v0.1.0.tar.gz"
+  sha256 "368095760ecc386a0930954f5f0ce7cea977641fe6d27b1beff032f512598a58"
 
-  head 'https://github.com/mururu/exenv.git'
+  head "https://github.com/mururu/exenv.git"
 
   def install
-    inreplace 'libexec/exenv', '/usr/local', HOMEBREW_PREFIX
-    prefix.install Dir['*']
+    inreplace "libexec/exenv", "/usr/local", HOMEBREW_PREFIX
+    prefix.install Dir["*"]
   end
 
   def caveats; <<-EOS.undent
     To use Homebrew's directories rather than ~/.exenv add to your profile:
-      export EXENV_ROOT=#{var}/exenv
+      export "EXENV_ROOT=#{var}/exenv"
 
     To enable shims and autocompletion add to your profile:
       if which exenv > /dev/null; then eval "$(exenv init -)"; fi
     EOS
   end
+
+  test do
+    system "#{bin}/exenv", "init", "-"
+  end
 end