Raise ArgumentError when a symbol can't be mapped to a version

The fact that this is implemented as a hash lookup is an implementation
detail, so don't let the KeyError bubble up.

1 files changed, 5 insertions, 0 deletions

diff --git a/Library/Homebrew/test/test_version_subclasses.rb b/Library/Homebrew/test/test_version_subclasses.rb
index 1dbaae47a..9261a7251 100644
--- a/Library/Homebrew/test/test_version_subclasses.rb
+++ b/Library/Homebrew/test/test_version_subclasses.rb
@@ -39,4 +39,9 @@ class MacOSVersionTests < Homebrew::TestCase
     assert_operator @v, :===, Version.new("10.7")
     assert_operator @v, :<, Version.new("10.8")
   end
+
+  def test_from_symbol
+    assert_equal @v, MacOS::Version.from_symbol(:lion)
+    assert_raises(ArgumentError) { MacOS::Version.from_symbol(:foo) }
+  end
 end