1 files changed, 29 insertions, 0 deletions
diff --git a/spec/ruby/core/string/unpack/at_spec.rb b/spec/ruby/core/string/unpack/at_spec.rb
new file mode 100644
index 0000000000..70cbebd2ba
--- /dev/null
+++ b/spec/ruby/core/string/unpack/at_spec.rb
@@ -0,0 +1,29 @@
+# -*- encoding: ascii-8bit -*-
+require File.expand_path('../../../../spec_helper', __FILE__)
+require File.expand_path('../../fixtures/classes', __FILE__)
+require File.expand_path('../shared/basic', __FILE__)
+
+describe "String#unpack with format '@'" do
+  it_behaves_like :string_unpack_basic, '@'
+  it_behaves_like :string_unpack_no_platform, '@'
+
+  it "moves the read index to the byte specified by the count" do
+    "\x01\x02\x03\x04".unpack("C3@2C").should == [1, 2, 3, 3]
+  end
+
+  it "implicitly has a count of zero when count is not specified" do
+    "\x01\x02\x03\x04".unpack("C2@C").should == [1, 2, 1]
+  end
+
+  it "has no effect when passed the '*' modifier" do
+    "\x01\x02\x03\x04".unpack("C2@*C").should == [1, 2, 3]
+  end
+
+  it "positions the read index one beyond the last readable byte in the String" do
+    "\x01\x02\x03\x04".unpack("C2@4C").should == [1, 2, nil]
+  end
+
+  it "raises an ArgumentError if the count exceeds the size of the String" do
+    lambda { "\x01\x02\x03\x04".unpack("C2@5C") }.should raise_error(ArgumentError)
+  end
+end