1 files changed, 65 insertions, 0 deletions
diff --git a/spec/ruby/core/argf/pos_spec.rb b/spec/ruby/core/argf/pos_spec.rb
new file mode 100644
index 0000000000..1ff16e4f17
--- /dev/null
+++ b/spec/ruby/core/argf/pos_spec.rb
@@ -0,0 +1,65 @@
+require_relative '../../spec_helper'
+
+describe "ARGF.pos" do
+  before :each do
+    @file1 = fixture __FILE__, "file1.txt"
+    @file2 = fixture __FILE__, "file2.txt"
+  end
+
+  it "gives the correct position for each read operation" do
+    argf [@file1, @file2] do
+      size1 = File.size(@file1)
+      size2 = File.size(@file2)
+
+      @argf.read(2)
+      @argf.pos.should == 2
+      @argf.read(size1-2)
+      @argf.pos.should == size1
+      @argf.read(6)
+      @argf.pos.should == 6
+      @argf.rewind
+      @argf.pos.should == 0
+      @argf.read(size2)
+      @argf.pos.should == size2
+    end
+  end
+
+  it "raises an ArgumentError when called on a closed stream" do
+    argf [@file1] do
+      @argf.read
+      -> { @argf.pos }.should.raise(ArgumentError)
+    end
+  end
+end
+
+describe "ARGF.pos=" do
+  before :each do
+    @file1_name = fixture __FILE__, "file1.txt"
+    @file2_name = fixture __FILE__, "file2.txt"
+
+    @file1 = File.readlines @file1_name
+    @file2 = File.readlines @file2_name
+  end
+
+  # NOTE: this test assumes that fixtures files have two lines each
+  it "sets the correct position in files" do
+    argf [@file1_name, @file2_name] do
+      @argf.pos = @file1.first.size
+      @argf.gets.should == @file1.last
+      @argf.pos = 0
+      @argf.gets.should == @file1.first
+
+      # finish reading file1
+      @argf.gets
+
+      @argf.gets
+      @argf.pos = 1
+      @argf.gets.should == @file2.first[1..-1]
+
+      @argf.pos = @file2.first.size + @file2.last.size - 1
+      @argf.gets.should == @file2.last[-1,1]
+      @argf.pos = 1000
+      @argf.read.should == ""
+    end
+  end
+end