1 files changed, 67 insertions, 0 deletions
diff --git a/spec/ruby/library/stringio/seek_spec.rb b/spec/ruby/library/stringio/seek_spec.rb
new file mode 100644
index 0000000000..9043e0338f
--- /dev/null
+++ b/spec/ruby/library/stringio/seek_spec.rb
@@ -0,0 +1,67 @@
+require_relative '../../spec_helper'
+require_relative 'fixtures/classes'
+
+describe "StringIO#seek" do
+  before :each do
+    @io = StringIO.new("12345678")
+  end
+
+  it "seeks from the current position when whence is IO::SEEK_CUR" do
+    @io.pos = 1
+    @io.seek(1, IO::SEEK_CUR)
+    @io.pos.should.eql?(2)
+
+    @io.seek(-1, IO::SEEK_CUR)
+    @io.pos.should.eql?(1)
+  end
+
+  it "seeks from the end of self when whence is IO::SEEK_END" do
+    @io.seek(3, IO::SEEK_END)
+    @io.pos.should.eql?(11) # Outside of the StringIO's content
+
+    @io.seek(-2, IO::SEEK_END)
+    @io.pos.should.eql?(6)
+  end
+
+  it "seeks to an absolute position when whence is IO::SEEK_SET" do
+    @io.seek(5, IO::SEEK_SET)
+    @io.pos.should == 5
+
+    @io.pos = 3
+    @io.seek(5, IO::SEEK_SET)
+    @io.pos.should == 5
+  end
+
+  it "raises an Errno::EINVAL error on negative amounts when whence is IO::SEEK_SET" do
+    -> { @io.seek(-5, IO::SEEK_SET) }.should.raise(Errno::EINVAL)
+  end
+
+  it "raises an Errno::EINVAL error on incorrect whence argument" do
+    -> { @io.seek(0, 3) }.should.raise(Errno::EINVAL)
+    -> { @io.seek(0, -1) }.should.raise(Errno::EINVAL)
+    -> { @io.seek(0, 2**16) }.should.raise(Errno::EINVAL)
+    -> { @io.seek(0, -2**16) }.should.raise(Errno::EINVAL)
+  end
+
+  it "tries to convert the passed Object to a String using #to_int" do
+    obj = mock("to_int")
+    obj.should_receive(:to_int).and_return(2)
+    @io.seek(obj)
+    @io.pos.should.eql?(2)
+  end
+
+  it "raises a TypeError when the passed Object can't be converted to an Integer" do
+    -> { @io.seek(Object.new) }.should.raise(TypeError)
+  end
+end
+
+describe "StringIO#seek when self is closed" do
+  before :each do
+    @io = StringIO.new("example")
+    @io.close
+  end
+
+  it "raises an IOError" do
+    -> { @io.seek(5) }.should.raise(IOError)
+  end
+end