1 files changed, 96 insertions, 0 deletions
diff --git a/spec/ruby/core/io/readpartial_spec.rb b/spec/ruby/core/io/readpartial_spec.rb
new file mode 100644
index 0000000000..16cb08dada
--- /dev/null
+++ b/spec/ruby/core/io/readpartial_spec.rb
@@ -0,0 +1,96 @@
+# -*- encoding: ascii-8bit -*-
+require File.expand_path('../../../spec_helper', __FILE__)
+require File.expand_path('../fixtures/classes', __FILE__)
+
+describe "IO#readpartial" do
+  before :each do
+    @rd, @wr = IO.pipe
+    @rd.binmode
+    @wr.binmode
+  end
+
+  after :each do
+    @rd.close unless @rd.closed?
+    @wr.close unless @wr.closed?
+  end
+
+  it "raises IOError on closed stream" do
+    lambda { IOSpecs.closed_io.readpartial(10) }.should raise_error(IOError)
+
+    @rd.close
+    lambda { @rd.readpartial(10) }.should raise_error(IOError)
+  end
+
+  it "reads at most the specified number of bytes" do
+    @wr.write("foobar")
+
+    # buffered read
+    @rd.read(1).should == 'f'
+    # return only specified number, not the whole buffer
+    @rd.readpartial(1).should == "o"
+  end
+
+  it "reads after ungetc with data in the buffer" do
+    @wr.write("foobar")
+    c = @rd.getc
+    @rd.ungetc(c)
+    @rd.readpartial(3).should == "foo"
+    @rd.readpartial(3).should == "bar"
+  end
+
+  it "reads after ungetc with multibyte characters in the buffer" do
+    @wr.write("∂φ/∂x = gaîté")
+    c = @rd.getc
+    @rd.ungetc(c)
+    @rd.readpartial(3).should == "\xE2\x88\x82"
+    @rd.readpartial(3).should == "\xCF\x86/"
+  end
+
+  it "reads after ungetc without data in the buffer" do
+    @wr.write("f")
+    c = @rd.getc
+    @rd.ungetc(c)
+    @rd.readpartial(2).should == "f"
+
+    # now, also check that the ungot char is cleared and
+    # not returned again
+    @wr.write("b")
+    @rd.readpartial(2).should == "b"
+  end
+
+  it "discards the existing buffer content upon successful read" do
+    buffer = "existing"
+    @wr.write("hello world")
+    @wr.close
+    @rd.readpartial(11, buffer)
+    buffer.should == "hello world"
+  end
+
+  it "raises EOFError on EOF" do
+    @wr.write("abc")
+    @wr.close
+    @rd.readpartial(10).should == 'abc'
+    lambda { @rd.readpartial(10) }.should raise_error(EOFError)
+  end
+
+  it "discards the existing buffer content upon error" do
+    buffer = 'hello'
+    @wr.close
+    lambda { @rd.readpartial(1, buffer) }.should raise_error(EOFError)
+    buffer.should be_empty
+  end
+
+  it "raises IOError if the stream is closed" do
+    @wr.close
+    lambda { @rd.readpartial(1) }.should raise_error(IOError)
+  end
+
+  it "raises ArgumentError if the negative argument is provided" do
+    lambda { @rd.readpartial(-1) }.should raise_error(ArgumentError)
+  end
+
+  it "immediately returns an empty string if the length argument is 0" do
+    @rd.readpartial(0).should == ""
+  end
+
+end