tests: add some emoji tests

Library/Homebrew/test/emoji_test.rb

+require "testing_env"
+require "emoji"
+
+class EmojiTest < Homebrew::TestCase
+  def test_install_badge
+    assert_equal "🍺", Emoji.install_badge
+
+    ENV["HOMEBREW_INSTALL_BADGE"] = "foo"
+    assert_equal "foo", Emoji.install_badge
+  end
+end

Library/Homebrew/test/utils_test.rb

@@ -9,6 +9,14 @@ class UtilTests < Homebrew::TestCase
     @dir = Pathname.new(mktmpdir)
   end
 
+  # Helper for matching escape sequences.
+  def e(code)
+    /(\e\[\d+m)*\e\[#{code}m/
+  end
+
+  # Helper for matching that style is reset at the end of a string.
+  Z = /(\e\[\d+m)*\e\[0m\Z/
+
   def test_ofail
     shutup { ofail "foo" }
     assert Homebrew.failed?
@@ -22,11 +30,25 @@ class UtilTests < Homebrew::TestCase
   end
 
   def test_pretty_installed
+    $stdout.stubs(:tty?).returns true
+    ENV.delete("HOMEBREW_NO_EMOJI")
+    assert_match(/\A#{e 1}foo #{e 32}✔#{Z}/, pretty_installed("foo"))
+
+    ENV["HOMEBREW_NO_EMOJI"] = "1"
+    assert_match(/\A#{e 1}foo \(installed\)#{Z}/, pretty_installed("foo"))
+
     $stdout.stubs(:tty?).returns false
     assert_equal "foo", pretty_installed("foo")
   end
 
   def test_pretty_uninstalled
+    $stdout.stubs(:tty?).returns true
+    ENV.delete("HOMEBREW_NO_EMOJI")
+    assert_match(/\A#{e 1}foo #{e 31}✘#{Z}/, pretty_uninstalled("foo"))
+
+    ENV["HOMEBREW_NO_EMOJI"] = "1"
+    assert_match(/\A#{e 1}foo \(uninstalled\)#{Z}/, pretty_uninstalled("foo"))
+
     $stdout.stubs(:tty?).returns false
     assert_equal "foo", pretty_uninstalled("foo")
   end