1 files changed, 137 insertions, 0 deletions
diff --git a/spec/ruby/core/io/sysread_spec.rb b/spec/ruby/core/io/sysread_spec.rb
new file mode 100644
index 0000000000..2d58db2250
--- /dev/null
+++ b/spec/ruby/core/io/sysread_spec.rb
@@ -0,0 +1,137 @@
+require_relative '../../spec_helper'
+require_relative 'fixtures/classes'
+
+describe "IO#sysread on a file" do
+  before :each do
+    @file_name = tmp("IO_sysread_file") + $$.to_s
+    File.open(@file_name, "w") do |f|
+      # write some stuff
+      f.write("012345678901234567890123456789\nabcdef")
+    end
+    @file = File.open(@file_name, "r+")
+  end
+
+  after :each do
+    @file.close
+    rm_r @file_name
+  end
+
+  it "reads the specified number of bytes from the file" do
+    @file.sysread(15).should == "012345678901234"
+  end
+
+  it "reads the specified number of bytes from the file to the buffer" do
+    buf = +"" # empty buffer
+    @file.sysread(15, buf).should == buf
+    buf.should == "012345678901234"
+
+    @file.rewind
+
+    buf = +"ABCDE" # small buffer
+    @file.sysread(15, buf).should == buf
+    buf.should == "012345678901234"
+
+    @file.rewind
+
+    buf = +"ABCDE" * 5 # large buffer
+    @file.sysread(15, buf).should == buf
+    buf.should == "012345678901234"
+  end
+
+  it "coerces the second argument to string and uses it as a buffer" do
+    buf = +"ABCDE"
+    (obj = mock("buff")).should_receive(:to_str).any_number_of_times.and_return(buf)
+    @file.sysread(15, obj).should == buf
+    buf.should == "012345678901234"
+  end
+
+  it "advances the position of the file by the specified number of bytes" do
+    @file.sysread(15)
+    @file.sysread(5).should == "56789"
+  end
+
+  it "raises an error when called after buffered reads" do
+    @file.readline
+    -> { @file.sysread(5) }.should.raise(IOError)
+  end
+
+  it "reads normally even when called immediately after a buffered IO#read" do
+    @file.read(15)
+    @file.sysread(5).should == "56789"
+  end
+
+  it "does not raise error if called after IO#read followed by IO#write" do
+    @file.read(5)
+    @file.write("abcde")
+    -> { @file.sysread(5) }.should_not.raise(IOError)
+  end
+
+  it "does not raise error if called after IO#read followed by IO#syswrite" do
+    @file.read(5)
+    @file.syswrite("abcde")
+    -> { @file.sysread(5) }.should_not.raise(IOError)
+  end
+
+  it "reads updated content after the flushed buffered IO#write" do
+    @file.write("abcde")
+    @file.flush
+    @file.sysread(5).should == "56789"
+    File.open(@file_name) do |f|
+      f.sysread(10).should == "abcde56789"
+    end
+  end
+
+  it "raises IOError on closed stream" do
+    -> { IOSpecs.closed_io.sysread(5) }.should.raise(IOError)
+  end
+
+  it "immediately returns an empty string if the length argument is 0" do
+    @file.sysread(0).should == ""
+  end
+
+  it "immediately returns the given buffer if the length argument is 0" do
+    buffer = +"existing content"
+    @file.sysread(0, buffer).should == buffer
+    buffer.should == "existing content"
+  end
+
+  it "discards the existing buffer content upon successful read" do
+    buffer = +"existing content"
+    @file.sysread(11, buffer).should.equal?(buffer)
+    buffer.should == "01234567890"
+  end
+
+  it "discards the existing buffer content upon error" do
+    buffer = +"existing content"
+    @file.seek(0, :END)
+    -> { @file.sysread(1, buffer) }.should.raise(EOFError)
+    buffer.should.empty?
+  end
+
+  it "preserves the encoding of the given buffer" do
+    buffer = ''.encode(Encoding::ISO_8859_1)
+    string = @file.sysread(10, buffer)
+
+    buffer.encoding.should == Encoding::ISO_8859_1
+  end
+end
+
+describe "IO#sysread" do
+  before do
+    @read, @write = IO.pipe
+  end
+
+  after do
+    @read.close
+    @write.close
+  end
+
+  it "returns a smaller string if less than size bytes are available" do
+    @write.syswrite "ab"
+    @read.sysread(3).should == "ab"
+  end
+
+  it "raises ArgumentError when length is less than 0" do
+    -> { @read.sysread(-1) }.should.raise(ArgumentError)
+  end
+end