Ensure Bisect::Channel is able to send data successfully when UTF-8 encoding is set

lib/rspec/core/bisect/utilities.rb

@@ -29,11 +29,22 @@ def publish(event, *args)
       end
 
       # Wraps a pipe to support sending objects between a child and
-      # parent process.
+      # parent process. Where supported, encoding is explicitly
+      # set to ensure binary data is able to pass from child to
+      # parent.
       # @private
       class Channel
+        if String.method_defined?(:encoding)
+          MARSHAL_DUMP_ENCODING = Marshal.dump("").encoding
+        end
+
         def initialize
           @read_io, @write_io = IO.pipe
+
+          if defined?(MARSHAL_DUMP_ENCODING) && IO.method_defined?(:set_encoding)
+            # Ensure the pipe can send any content produced by Marshal.dump
+            @write_io.set_encoding MARSHAL_DUMP_ENCODING
+          end
         end
 
         def send(message)

spec/rspec/core/bisect/utilities_spec.rb

@@ -36,5 +36,41 @@ def foo(notification); end
 
       expect(channel.receive).to eq :value_from_child
     end
+
+    describe "in a UTF-8 encoding context (where possible)" do
+      if defined?(Encoding)
+        around(:each) do |example|
+          old_external = old_internal = nil
+
+          ignoring_warnings do
+            old_external, Encoding.default_external = Encoding.default_external, Encoding::UTF_8
+            old_internal, Encoding.default_internal = Encoding.default_internal, Encoding::UTF_8
+          end
+
+          example.run
+
+          ignoring_warnings do
+            Encoding.default_external = old_external
+            Encoding.default_internal = old_internal
+          end
+        end
+      end
+
+      it "successfully sends binary data within a process" do
+        channel = Bisect::Channel.new
+        expect { channel.send("\xF8") }.not_to raise_error
+      end
+
+      it "successfully sends binary data from a child process to its parent process" do
+        channel = Bisect::Channel.new
+
+        in_sub_process do
+          channel.send("\xF8")
+        end
+
+        expect(channel.receive).to eq("\xF8")
+      end
+    end
+
   end
 end