Fix bad test coverage

One typo, one debug test
Also stop producing those object files, use in memory io

test/elf/helper.rb

@@ -10,10 +10,10 @@ module Elf
     def as_main(input)
       in_space("def main(arg);#{input};end")
     end
-    def check(input, file)
+    def check(input)
       linker = RubyX::RubyXCompiler.new(RubyX.default_test_options).ruby_to_binary( input , :arm )
       writer = Elf::ObjectWriter.new(linker)
-      writer.save "test/#{file}.o"
+      writer.save StringIO.new
     end
   end
 end

test/elf/test_something.rb

@@ -23,7 +23,7 @@ module Elf
       end
 HERE
       @exit_code = 4
-      check get_preload("Integer.lt;Integer.plus") + in_space(input) , "fibo"
+      check get_preload("Integer.lt;Integer.plus") + in_space(input) 
     end
   end
 end

test/elf/test_somethingelse.rb

@@ -9,7 +9,7 @@ module Elf
       preload = "class Word < Data8;def putstring;X.putstring;end;end;"
       @stdout = hello
       @exit_code = hello.length
-      check preload + as_main(input), "hello"
+      check preload + as_main(input)
     end
   end
 end

test/elf/test_zero.rb

@@ -11,8 +11,12 @@ module Elf
 
     def test_empty_translate
       writer = Elf::ObjectWriter.new(@linker )
-      writer.save "test/zero.o"
+      writer.save StringIO.new
     end
 
+    def test_empty_translate_with_debug
+      writer = Elf::ObjectWriter.new(@linker , debug: true )
+      writer.save StringIO.new
+    end
   end
 end