From 01735bb17a22bd62bc516697f93a22bb9cdc5d07 Mon Sep 17 00:00:00 2001
From: Scott Taylor <scott@railsnewbie.com>
Date: Tue, 12 Jan 2010 00:16:18 -0500
Subject: [PATCH] Implement File#sysseek

---
 lib/fakefs/file.rb             |  5 ++--
 test/fake/file/sysseek_test.rb | 44 ++++++++++++++++++++++++++++++++++
 2 files changed, 47 insertions(+), 2 deletions(-)
 create mode 100644 test/fake/file/sysseek_test.rb

diff --git a/lib/fakefs/file.rb b/lib/fakefs/file.rb
index 1939340..65f6e0a 100644
--- a/lib/fakefs/file.rb
+++ b/lib/fakefs/file.rb
@@ -239,8 +239,9 @@ module FakeFS
       raise NotImplementedError
     end
 
-    def sysseek(offset, whence = SEEK_SET)
-      raise NotImplementedError
+    def sysseek(position, whence = SEEK_SET)
+      seek(position, whence)
+      pos
     end
 
     alias_method :to_i, :fileno
diff --git a/test/fake/file/sysseek_test.rb b/test/fake/file/sysseek_test.rb
new file mode 100644
index 0000000..531b21a
--- /dev/null
+++ b/test/fake/file/sysseek_test.rb
@@ -0,0 +1,44 @@
+require "test_helper"
+
+class FileSysSeek < Test::Unit::TestCase
+  def setup
+    FakeFS.activate!
+    FakeFS::FileSystem.clear
+  end
+
+  def teardown
+    FakeFS.deactivate!
+  end
+
+  def test_should_seek_to_position
+    file = File.open("foo", "w") do |f|
+      f << "0123456789"
+    end
+
+    File.open("foo", "r") do |f|
+      f.sysseek(3)
+      assert_equal 3, f.pos
+
+      f.sysseek(0)
+      assert_equal 0, f.pos
+    end
+  end
+
+  def test_seek_returns_offset_into_file
+    File.open("foo", "w") do |f|
+      # 66 chars long
+      str = "0123456789" +
+            "0123456789" +
+            "0123456789" +
+            "0123456789" +
+            "0123456789" +
+            "0123456789" +
+            "012345"
+
+      f << str
+    end
+
+    f = File.open("foo")
+    assert_equal 53, f.sysseek(-13, IO::SEEK_END)
+  end
+end
\ No newline at end of file