Some changes around Rbx and JRuby

Rbx passes all specs, and looks like feature issues are
due to different presentation style of backtrace

JRuby has one failing spec, but gets totally destroyed
in the cukes b/c it's interface to Open3.capture3 is
apparently different (looks like it ultimately delegates
to IO.popen, but haven't tracked that code down yet

This is part of #31

lib/seeing_is_believing/wrap_expressions.rb

@@ -167,7 +167,11 @@ def find_wrappings(ast=root)
         range = ast.location.expression
 
         # first two children: target, message, so we want the last child only if it is an argument
-        target, message, *, last_arg = ast.children
+        children = ast.children
+        target   = children[0]
+        message  = children[1]
+        last_arg = children.size > 2 ? children[-1] : nil
+
 
         # last arg is a heredoc, use the closing paren, or the end of the first line of the heredoc
         if heredoc? last_arg

spec/evaluate_by_moving_files_spec.rb

@@ -97,7 +97,14 @@ def invoke(program, options={})
   end
 
   it 'will set the encoding' do
-    invoke('print "ç"', encoding: 'u').stdout.should == "ç"
+    test = -> { invoke('print "ç"', encoding: 'u').stdout.should == "ç" }
+    if defined?(RUBY_ENGINE) && RUBY_ENGINE == 'rbx'
+      pending "Rubinius doesn't seem to use -Kx, but rather -U" do
+        test.call
+      end
+    else
+      test.call
+    end
   end
 
   it 'if it fails, it prints some debugging information and raises an error' do

spec/hard_core_ensure_spec.rb

@@ -41,18 +41,25 @@ def call(options)
   end
 
   it 'invokes the code even if an interrupt is sent and there is a default handler' do
-    channel = IChannel.new Marshal
-    pid = fork do
-      old_handler = trap('INT') { channel.put "old handler invoked" }
-      call code: -> { sleep 0.1 }, ensure: -> { channel.put "ensure invoked" }
-      trap 'INT', old_handler
+    test = lambda do
+      channel = IChannel.new Marshal
+      pid = fork do
+        old_handler = trap('INT') { channel.put "old handler invoked" }
+        call code: -> { sleep 0.1 }, ensure: -> { channel.put "ensure invoked" }
+        trap 'INT', old_handler
+      end
+      sleep 0.05
+      Process.kill 'INT', pid
+      Process.wait pid
+      channel.get.should == "ensure invoked"
+      channel.get.should == "old handler invoked"
+      channel.should_not be_readable
+    end
+    if defined?(RUBY_ENGINE) && RUBY_ENGINE == 'jruby'
+      pending "Skipping this test on jruby b/c the JVM doesn't have a fork"
+    else
+      test.call
     end
-    sleep 0.05
-    Process.kill 'INT', pid
-    Process.wait pid
-    channel.get.should == "ensure invoked"
-    channel.get.should == "old handler invoked"
-    channel.should_not be_readable
   end
 
   it 'invokes the code even if an interrupt is sent and interrupts are set to ignore' do
@@ -72,10 +79,12 @@ def call(options)
       channel.should_not be_readable
     end
 
-    if RUBY_VERSION == '2.1.1' || RUBY_VERSION == '2.1.2'
-      pending 'This test can\'t run on 2.1.1 or 2.1.2'
+    if defined?(RUBY_ENGINE) && RUBY_ENGINE == 'jruby'
+      pending "Skipping this test on jruby b/c the JVM doesn't have a fork"
+    elsif (!defined?(RUBY_ENGINE) || RUBY_ENGINE == 'ruby') && (RUBY_VERSION == '2.1.1' || RUBY_VERSION == '2.1.2')
+      pending 'This test can\'t run on MRI (2.1.1 or 2.1.2) b/c of bug, see https://github.com/JoshCheek/seeing_is_believing/issues/26'
     else
-      test.call
+      test.call # e.g. works on Rubinius
     end
   end
 end