1 files changed, 28 insertions, 0 deletions
diff --git a/spec/ruby/library/stringio/set_encoding_spec.rb b/spec/ruby/library/stringio/set_encoding_spec.rb
new file mode 100644
index 0000000000..19ca0875bf
--- /dev/null
+++ b/spec/ruby/library/stringio/set_encoding_spec.rb
@@ -0,0 +1,28 @@
+require 'stringio'
+require_relative '../../spec_helper'
+
+describe "StringIO#set_encoding" do
+  it "sets the encoding of the underlying String if the String is not frozen" do
+    str = "".encode(Encoding::US_ASCII)
+
+    io = StringIO.new(str)
+    io.set_encoding Encoding::UTF_8
+    io.string.encoding.should == Encoding::UTF_8
+  end
+
+  it "does not set the encoding of the underlying String if the String is frozen" do
+    str = "".encode(Encoding::US_ASCII).freeze
+
+    io = StringIO.new(str)
+    io.set_encoding Encoding::UTF_8
+    io.string.encoding.should == Encoding::US_ASCII
+  end
+
+  it "accepts a String" do
+    str = "".encode(Encoding::US_ASCII)
+    io = StringIO.new(str)
+    io.set_encoding("ASCII-8BIT")
+    io.external_encoding.should == Encoding::BINARY
+    str.encoding.should == Encoding::BINARY
+  end
+end