Fix incompatible encodings error in junit formatter

lib/cucumber/formatter/interceptor.rb

@@ -8,7 +8,7 @@ class Pipe
         attr_reader :pipe
         def initialize(pipe)
           @pipe = pipe
-          @buffer = []
+          @buffer = StringIO.new
           @wrapped = true
         end
 
@@ -19,9 +19,16 @@ def write(str)
           end
         end
 
+        # @deprecated use #buffer_string
         def buffer
           lock.synchronize do
-            return @buffer.dup
+            return @buffer.string.lines
+          end
+        end
+
+        def buffer_string
+          lock.synchronize do
+            return @buffer.string.dup
           end
         end
 

lib/cucumber/formatter/junit.rb

@@ -140,10 +140,10 @@ def build_testcase(result, scenario_designation, output)
             @current_feature_data[:failures] += 1
           end
           @current_feature_data[:builder].tag!('system-out') do
-            @current_feature_data[:builder].cdata! strip_control_chars(@interceptedout.buffer.join)
+            @current_feature_data[:builder].cdata! strip_control_chars(@interceptedout.buffer_string)
           end
           @current_feature_data[:builder].tag!('system-err') do
-            @current_feature_data[:builder].cdata! strip_control_chars(@interceptederr.buffer.join)
+            @current_feature_data[:builder].cdata! strip_control_chars(@interceptederr.buffer_string)
           end
         end
         @current_feature_data[:tests] += 1

spec/cucumber/formatter/interceptor_spec.rb

@@ -114,6 +114,7 @@ module Cucumber::Formatter
 
         expect(pi.buffer).not_to be_empty
         expect(pi.buffer.first).to eq buffer
+        expect(pi.buffer_string).to eq buffer
       end
     end