1 files changed, 64 insertions, 0 deletions
diff --git a/spec/ruby/core/array/pack/x_spec.rb b/spec/ruby/core/array/pack/x_spec.rb
new file mode 100644
index 0000000000..8d54ab84ee
--- /dev/null
+++ b/spec/ruby/core/array/pack/x_spec.rb
@@ -0,0 +1,64 @@
+# -*- 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 "Array#pack with format 'x'" do
+  it_behaves_like :array_pack_basic, 'x'
+  it_behaves_like :array_pack_basic_non_float, 'x'
+  it_behaves_like :array_pack_no_platform, 'x'
+
+  it "adds a NULL byte with an empty array" do
+    [].pack("x").should == "\x00"
+  end
+
+  it "adds a NULL byte without consuming an element" do
+    [1, 2].pack("CxC").should == "\x01\x00\x02"
+  end
+
+  it "is not affected by a previous count modifier" do
+    [].pack("x3x").should == "\x00\x00\x00\x00"
+  end
+
+  it "adds multiple NULL bytes when passed a count modifier" do
+    [].pack("x3").should == "\x00\x00\x00"
+  end
+
+  it "does not add a NULL byte if the count modifier is zero" do
+    [].pack("x0").should == ""
+  end
+
+  it "does not add a NULL byte when passed the '*' modifier" do
+    [].pack("x*").should == ""
+  end
+end
+
+describe "Array#pack with format 'X'" do
+  it_behaves_like :array_pack_basic, 'X'
+  it_behaves_like :array_pack_basic_non_float, 'X'
+  it_behaves_like :array_pack_no_platform, 'X'
+
+  it "reduces the output string by one byte at the point it is encountered" do
+    [1, 2, 3].pack("C2XC").should == "\x01\x03"
+  end
+
+  it "does not consume any elements" do
+    [1, 2, 3].pack("CXC").should == "\x02"
+  end
+
+  it "reduces the output string by multiple bytes when passed a count modifier" do
+    [1, 2, 3, 4, 5].pack("C2X2C").should == "\x03"
+  end
+
+  it "has no affect when passed the '*' modifier" do
+    [1, 2, 3].pack("C2X*C").should == "\x01\x02\x03"
+  end
+
+  it "raises an ArgumentError if the output string is empty" do
+    lambda { [1, 2, 3].pack("XC") }.should raise_error(ArgumentError)
+  end
+
+  it "raises an ArgumentError if the count modifier is greater than the bytes in the string" do
+    lambda { [1, 2, 3].pack("C2X3") }.should raise_error(ArgumentError)
+  end
+end