Extensions aren't actually required

test/test_language.rb

@@ -349,12 +349,6 @@ class TestLanguage < Test::Unit::TestCase
     assert_equal '.coffee', Language['CoffeeScript'].primary_extension
     assert_equal '.t', Language['Turing'].primary_extension
     assert_equal '.ts', Language['TypeScript'].primary_extension
-
-    # This is a nasty requirement, but there's some code in GitHub that
-    # expects this. Really want to drop this.
-    Language.all.each do |language|
-      assert language.primary_extension, "#{language} has no primary extension"
-    end
   end
 
   def test_eql