1 files changed, 80 insertions, 0 deletions
diff --git a/spec/ruby/library/stringio/readpartial_spec.rb b/spec/ruby/library/stringio/readpartial_spec.rb
new file mode 100644
index 0000000000..e65e50fa41
--- /dev/null
+++ b/spec/ruby/library/stringio/readpartial_spec.rb
@@ -0,0 +1,80 @@
+require File.expand_path('../../../spec_helper', __FILE__)
+require File.expand_path('../fixtures/classes', __FILE__)
+
+describe "StringIO#readpartial" do
+  before :each do
+    @string = StringIO.new('Stop, look, listen')
+  end
+
+  after :each do
+    @string.close unless @string.closed?
+  end
+
+  it "raises IOError on closed stream" do
+    @string.close
+    lambda { @string.readpartial(10) }.should raise_error(IOError)
+  end
+
+  it "reads at most the specified number of bytes" do
+
+    # buffered read
+    @string.read(1).should == 'S'
+    # return only specified number, not the whole buffer
+    @string.readpartial(1).should == "t"
+  end
+
+  it "reads after ungetc with data in the buffer" do
+    c = @string.getc
+    @string.ungetc(c)
+    @string.readpartial(4).should == "Stop"
+    @string.readpartial(3).should == ", l"
+  end
+
+  it "reads after ungetc without data in the buffer" do
+    @string = StringIO.new
+    @string.write("f").should == 1
+    @string.rewind
+    c = @string.getc
+    c.should == 'f'
+    @string.ungetc(c).should == nil
+
+    @string.readpartial(2).should == "f"
+    @string.rewind
+    # now, also check that the ungot char is cleared and
+    # not returned again
+    @string.write("b").should == 1
+    @string.rewind
+    @string.readpartial(2).should == "b"
+  end
+
+  it "discards the existing buffer content upon successful read" do
+    buffer = "existing"
+    @string.readpartial(11, buffer)
+    buffer.should == "Stop, look,"
+  end
+
+  it "raises EOFError on EOF" do
+    @string.readpartial(18).should == 'Stop, look, listen'
+    lambda { @string.readpartial(10) }.should raise_error(EOFError)
+  end
+
+  it "discards the existing buffer content upon error" do
+    buffer = 'hello'
+    @string.readpartial(100)
+    lambda { @string.readpartial(1, buffer) }.should raise_error(EOFError)
+    buffer.should be_empty
+  end
+
+  it "raises IOError if the stream is closed" do
+    @string.close
+    lambda { @string.readpartial(1) }.should raise_error(IOError)
+  end
+
+  it "raises ArgumentError if the negative argument is provided" do
+    lambda { @string.readpartial(-1) }.should raise_error(ArgumentError)
+  end
+
+  it "immediately returns an empty string if the length argument is 0" do
+    @string.readpartial(0).should == ""
+  end
+end