1 files changed, 106 insertions, 0 deletions
diff --git a/spec/ruby/core/io/dup_spec.rb b/spec/ruby/core/io/dup_spec.rb
new file mode 100644
index 0000000000..db4e9fe641
--- /dev/null
+++ b/spec/ruby/core/io/dup_spec.rb
@@ -0,0 +1,106 @@
+require_relative '../../spec_helper'
+require_relative 'fixtures/classes'
+
+describe "IO#dup" do
+  before :each do
+    @file = tmp("spec_io_dup")
+    @f = File.open @file, 'w+'
+    @i = @f.dup
+
+    @f.sync = true
+    @i.sync = true
+  end
+
+  after :each do
+    @i.close if @i && !@i.closed?
+    @f.close if @f && !@f.closed?
+    rm_r @file
+  end
+
+  it "returns a new IO instance" do
+    @i.class.should == @f.class
+  end
+
+  it "sets a new descriptor on the returned object" do
+    @i.fileno.should_not == @f.fileno
+  end
+
+  quarantine! do # This does not appear to be consistent across platforms
+    it "shares the original stream between the two IOs" do
+      start = @f.pos
+      @i.pos.should == start
+
+      s =  "Hello, wo.. wait, where am I?\n"
+      s2 = "<evil voice>       Muhahahaa!"
+
+      @f.write s
+      @i.pos.should == @f.pos
+
+      @i.rewind
+      @i.gets.should == s
+
+      @i.rewind
+      @i.write s2
+
+      @f.rewind
+      @f.gets.should == "#{s2}\n"
+    end
+  end
+
+  it "allows closing the new IO without affecting the original" do
+    @i.close
+    -> { @f.gets }.should_not.raise(Exception)
+
+    @i.should.closed?
+    @f.should_not.closed?
+  end
+
+  it "allows closing the original IO without affecting the new one" do
+    @f.close
+    -> { @i.gets }.should_not.raise(Exception)
+
+    @i.should_not.closed?
+    @f.should.closed?
+  end
+
+  it "raises IOError on closed stream" do
+    -> { IOSpecs.closed_io.dup }.should.raise(IOError)
+  end
+
+  it "always sets the close-on-exec flag for the new IO object" do
+    @f.close_on_exec = true
+    dup = @f.dup
+    begin
+      dup.should.close_on_exec?
+    ensure
+      dup.close
+    end
+
+    @f.close_on_exec = false
+    dup = @f.dup
+    begin
+      dup.should.close_on_exec?
+    ensure
+      dup.close
+    end
+  end
+
+  it "always sets the autoclose flag for the new IO object" do
+    @f.autoclose = true
+    dup = @f.dup
+    begin
+      dup.should.autoclose?
+    ensure
+      dup.close
+    end
+
+    @f.autoclose = false
+    dup = @f.dup
+    begin
+      dup.should.autoclose?
+    ensure
+      dup.close
+      @f.autoclose = true
+    end
+  end
+end