1 files changed, 47 insertions, 39 deletions
diff --git a/spec/ruby/core/array/pack/buffer_spec.rb b/spec/ruby/core/array/pack/buffer_spec.rb
index 928f7db731..b77b2d1efa 100644
--- a/spec/ruby/core/array/pack/buffer_spec.rb
+++ b/spec/ruby/core/array/pack/buffer_spec.rb
@@ -1,52 +1,60 @@
-# encoding: ascii-8bit
+# encoding: binary
 
-require File.expand_path('../../../../spec_helper', __FILE__)
+require_relative '../../../spec_helper'
 
-ruby_version_is '2.4' do
-  describe "Aray#pack with `buffer` option" do
-    it "returns specified buffer" do
-      n = [ 65, 66, 67 ]
-      buffer = " "*3
-      result = n.pack("ccc", buffer: buffer)      #=> "ABC"
-      result.should equal(buffer)
-    end
+describe "Array#pack with :buffer option" do
+  it "returns specified buffer" do
+    n = [ 65, 66, 67 ]
+    buffer = " "*3
+    result = n.pack("ccc", buffer: buffer)      #=> "ABC"
+    result.should equal(buffer)
+  end
+
+  it "adds result at the end of buffer content" do
+    n = [ 65, 66, 67 ] # result without buffer is "ABC"
+
+    buffer = +""
+    n.pack("ccc", buffer: buffer).should == "ABC"
+
+    buffer = +"123"
+    n.pack("ccc", buffer: buffer).should == "123ABC"
+
+    buffer = +"12345"
+    n.pack("ccc", buffer: buffer).should == "12345ABC"
+  end
 
-    it "adds result at the end of buffer content" do
-      n = [ 65, 66, 67 ] # result without buffer is "ABC"
+  it "raises TypeError exception if buffer is not String" do
+    -> { [65].pack("ccc", buffer: []) }.should raise_error(
+      TypeError, "buffer must be String, not Array")
+  end
 
-      buffer = ""
-      n.pack("ccc", buffer: buffer).should == "ABC"
+  it "raise FrozenError if buffer is frozen" do
+    -> { [65].pack("c", buffer: "frozen-string".freeze) }.should raise_error(FrozenError)
+  end
 
-      buffer = "123"
-      n.pack("ccc", buffer: buffer).should == "123ABC"
+  it "preserves the encoding of the given buffer" do
+    buffer = ''.encode(Encoding::ISO_8859_1)
+    [65, 66, 67].pack("ccc", buffer: buffer)
+    buffer.encoding.should == Encoding::ISO_8859_1
+  end
 
-      buffer = "12345"
-      n.pack("ccc", buffer: buffer).should == "12345ABC"
+  context "offset (@) is specified" do
+    it 'keeps buffer content if it is longer than offset' do
+      n = [ 65, 66, 67 ]
+      buffer = +"123456"
+      n.pack("@3ccc", buffer: buffer).should == "123ABC"
     end
 
-    it "raises TypeError exception if buffer is not String" do
-      lambda { [65].pack("ccc", buffer: []) }.should raise_error(
-        TypeError, "buffer must be String, not Array")
+    it "fills the gap with \\0 if buffer content is shorter than offset" do
+      n = [ 65, 66, 67 ]
+      buffer = +"123"
+      n.pack("@6ccc", buffer: buffer).should == "123\0\0\0ABC"
     end
 
-    context "offset (@) is specified" do
-      it 'keeps buffer content if it is longer than offset' do
-        n = [ 65, 66, 67 ]
-        buffer = "123456"
-        n.pack("@3ccc", buffer: buffer).should == "123ABC"
-      end
-
-      it "fills the gap with \0 if buffer content is shorter than offset" do
-        n = [ 65, 66, 67 ]
-        buffer = "123"
-        n.pack("@6ccc", buffer: buffer).should == "123\0\0\0ABC"
-      end
-
-      it 'does not keep buffer content if it is longer than offset + result' do
-        n = [ 65, 66, 67 ]
-        buffer = "1234567890"
-        n.pack("@3ccc", buffer: buffer).should == "123ABC"
-      end
+    it 'does not keep buffer content if it is longer than offset + result' do
+      n = [ 65, 66, 67 ]
+      buffer = +"1234567890"
+      n.pack("@3ccc", buffer: buffer).should == "123ABC"
     end
   end
 end