1 files changed, 49 insertions, 0 deletions
diff --git a/spec/ruby/core/io/try_convert_spec.rb b/spec/ruby/core/io/try_convert_spec.rb
new file mode 100644
index 0000000000..7600b01b75
--- /dev/null
+++ b/spec/ruby/core/io/try_convert_spec.rb
@@ -0,0 +1,49 @@
+require_relative '../../spec_helper'
+require_relative 'fixtures/classes'
+
+describe "IO.try_convert" do
+  before :each do
+    @name = tmp("io_try_convert.txt")
+    @io = new_io @name
+  end
+
+  after :each do
+    @io.close unless @io.closed?
+    rm_r @name
+  end
+
+  it "returns the passed IO object" do
+    IO.try_convert(@io).should.equal?(@io)
+  end
+
+  it "does not call #to_io on an IO instance" do
+    @io.should_not_receive(:to_io)
+    IO.try_convert(@io)
+  end
+
+  it "calls #to_io to coerce an object" do
+    obj = mock("io")
+    obj.should_receive(:to_io).and_return(@io)
+    IO.try_convert(obj).should.equal?(@io)
+  end
+
+  it "returns nil when the passed object does not respond to #to_io" do
+    IO.try_convert(mock("io")).should == nil
+  end
+
+  it "return nil when BasicObject is passed" do
+    IO.try_convert(BasicObject.new).should == nil
+  end
+
+  it "raises a TypeError if the object does not return an IO from #to_io" do
+    obj = mock("io")
+    obj.should_receive(:to_io).and_return("io")
+    -> { IO.try_convert(obj) }.should raise_consistent_error(TypeError, "can't convert MockObject into IO (MockObject#to_io gives String)")
+  end
+
+  it "propagates an exception raised by #to_io" do
+    obj = mock("io")
+    obj.should_receive(:to_io).and_raise(TypeError.new)
+    ->{ IO.try_convert(obj) }.should.raise(TypeError)
+  end
+end