io.c: opening external command

* io.c (rb_io_open_generic): try to open the named file as usual,
  if klass is not IO nor File, so that Errno::ENOENT will be
  raised probably.  calling on File will be same in the future.

From: Nobuyoshi Nakada <nobu@ruby-lang.org>

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@61320 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 3 insertions, 2 deletions

diff --git a/test/ruby/test_io.rb b/test/ruby/test_io.rb
index 4f6027d8c9..bb16953e99 100644
--- a/test/ruby/test_io.rb
+++ b/test/ruby/test_io.rb
@@ -2185,16 +2185,17 @@ class TestIO < Test::Unit::TestCase
   end
 
   def test_read_command
+    assert_equal("foo\n", IO.read("|echo foo"))
     assert_warn(/invoke external command/) do
       File.read("|#{EnvUtil.rubybin} -e puts")
     end
     assert_warn(/invoke external command/) do
       File.binread("|#{EnvUtil.rubybin} -e puts")
     end
-    assert_raise_with_message(ArgumentError, /invoke external command/) do
+    assert_raise(Errno::ENOENT) do
       Class.new(IO).read("|#{EnvUtil.rubybin} -e puts")
     end
-    assert_raise_with_message(ArgumentError, /invoke external command/) do
+    assert_raise(Errno::ENOENT) do
       Class.new(IO).binread("|#{EnvUtil.rubybin} -e puts")
     end
   end