test_stringio.rb: test_initialize

* test/stringio/test_stringio.rb (test_initialize): add test for
  StringIO#initialize.  [ruby-core:72585] [Feature #11920]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@53378 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

2 files changed, 26 insertions, 0 deletions

diff --git a/ChangeLog b/ChangeLog
index dcbfbf59c5..c41a9689f8 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Wed Dec 30 08:43:59 2015  Yuki Kurihara  <co000ri@gmail.com>
+
+	* test/stringio/test_stringio.rb (test_initialize): add test for
+	  StringIO#initialize.  [ruby-core:72585] [Feature #11920]
+
 Wed Dec 30 05:19:24 2015  Eric Wong  <e@80x24.org>
 
 	* class.c (struct clone_const_arg): adjust for id_table
diff --git a/test/stringio/test_stringio.rb b/test/stringio/test_stringio.rb
index 9a041c2148..77a98726d8 100644
--- a/test/stringio/test_stringio.rb
+++ b/test/stringio/test_stringio.rb
@@ -13,6 +13,27 @@ class TestStringIO < Test::Unit::TestCase
 
   include TestEOF::Seek
 
+  def test_initialize
+    assert_kind_of StringIO, StringIO.new
+    assert_kind_of StringIO, StringIO.new('str')
+    assert_kind_of StringIO, StringIO.new('str', 'r+')
+    assert_raise(ArgumentError) { StringIO.new('', 'x') }
+    assert_raise(ArgumentError) { StringIO.new('', 'rx') }
+    assert_raise(ArgumentError) { StringIO.new('', 'rbt') }
+    assert_raise(TypeError) { StringIO.new(nil) }
+    assert_raise(TypeError) { StringIO.new('str', nil) }
+
+    o = Object.new
+    def o.to_str
+      nil
+    end
+    assert_raise(TypeError) { StringIO.new(o) }
+    def o.to_str
+      'str'
+    end
+    assert_kind_of StringIO, StringIO.new(o)
+  end
+
   def test_truncate
     io = StringIO.new("")
     io.puts "abc"