1 files changed, 32 insertions, 13 deletions
diff --git a/spec/ruby/core/io/readpartial_spec.rb b/spec/ruby/core/io/readpartial_spec.rb
index 16cb08dada..d3f5545c8f 100644
--- a/spec/ruby/core/io/readpartial_spec.rb
+++ b/spec/ruby/core/io/readpartial_spec.rb
@@ -1,6 +1,6 @@
-# -*- encoding: ascii-8bit -*-
-require File.expand_path('../../../spec_helper', __FILE__)
-require File.expand_path('../fixtures/classes', __FILE__)
+# encoding: binary
+require_relative '../../spec_helper'
+require_relative 'fixtures/classes'
 
 describe "IO#readpartial" do
   before :each do
@@ -15,10 +15,10 @@ describe "IO#readpartial" do
   end
 
   it "raises IOError on closed stream" do
-    lambda { IOSpecs.closed_io.readpartial(10) }.should raise_error(IOError)
+    -> { IOSpecs.closed_io.readpartial(10) }.should.raise(IOError)
 
     @rd.close
-    lambda { @rd.readpartial(10) }.should raise_error(IOError)
+    -> { @rd.readpartial(10) }.should.raise(IOError)
   end
 
   it "reads at most the specified number of bytes" do
@@ -59,10 +59,10 @@ describe "IO#readpartial" do
   end
 
   it "discards the existing buffer content upon successful read" do
-    buffer = "existing"
+    buffer = +"existing content"
     @wr.write("hello world")
     @wr.close
-    @rd.readpartial(11, buffer)
+    @rd.readpartial(11, buffer).should.equal?(buffer)
     buffer.should == "hello world"
   end
 
@@ -70,27 +70,46 @@ describe "IO#readpartial" do
     @wr.write("abc")
     @wr.close
     @rd.readpartial(10).should == 'abc'
-    lambda { @rd.readpartial(10) }.should raise_error(EOFError)
+    -> { @rd.readpartial(10) }.should.raise(EOFError)
   end
 
   it "discards the existing buffer content upon error" do
-    buffer = 'hello'
+    buffer = +'hello'
     @wr.close
-    lambda { @rd.readpartial(1, buffer) }.should raise_error(EOFError)
-    buffer.should be_empty
+    -> { @rd.readpartial(1, buffer) }.should.raise(EOFError)
+    buffer.should.empty?
   end
 
   it "raises IOError if the stream is closed" do
     @wr.close
-    lambda { @rd.readpartial(1) }.should raise_error(IOError)
+    -> { @rd.readpartial(1) }.should.raise(IOError)
   end
 
   it "raises ArgumentError if the negative argument is provided" do
-    lambda { @rd.readpartial(-1) }.should raise_error(ArgumentError)
+    -> { @rd.readpartial(-1) }.should.raise(ArgumentError)
   end
 
   it "immediately returns an empty string if the length argument is 0" do
     @rd.readpartial(0).should == ""
   end
 
+  it "raises IOError if the stream is closed and the length argument is 0" do
+    @rd.close
+    -> { @rd.readpartial(0) }.should.raise(IOError, "closed stream")
+  end
+
+  it "clears and returns the given buffer if the length argument is 0" do
+    buffer = +"existing content"
+    @rd.readpartial(0, buffer).should == buffer
+    buffer.should == ""
+  end
+
+  it "preserves the encoding of the given buffer" do
+    buffer = ''.encode(Encoding::ISO_8859_1)
+    @wr.write("abc")
+    @wr.close
+    @rd.readpartial(10, buffer)
+
+    buffer.encoding.should == Encoding::ISO_8859_1
+  end
 end