diff --git a/test/mains/helper.rb b/test/mains/helper.rb
index bb161258..23136d36 100644
--- a/test/mains/helper.rb
+++ b/test/mains/helper.rb
@@ -1,4 +1,79 @@
 require_relative '../helper'
 
 module Mains
+  module MainsHelper
+    include Preloader
+    include ScopeHelper
+
+    def setup
+      @qemu = ENV["qemu-arm"] || "qemu-arm"
+      @linker = ENV["arm-linux-gnu-ld"] || "arm-linux-gnu-ld"  #on fedora
+      @arm = ENV["TEST_ARM"] or ENV["TEST_ALL"]
+      #@linker = "arm-linux-gnueabi-ld"  # on ubuntu
+      # ENV["TEST_ARM"] = "DEBUG"
+    end
+
+    def assert_result( exit_code , stdout , name = nil)
+      name = caller_locations.first.label unless name
+      input = preload + @input
+      code , out = run_interpreter( input , name)
+      assert_equal exit_code , code , "interpreter code for #{name}"
+      assert_equal stdout , out , "interpreter stdout for #{name}"
+      return unless @arm
+      code , out = run_arm( input , name)
+      assert_equal exit_code , code , "arm code for #{name}"
+      assert_equal stdout , out , "arm stdout for #{name}"
+    end
+
+    # runnable_methods is called by minitest to determine which tests to run
+    def self.runnable_methods
+      all = Dir["test/mains/source/*_*.rb"]
+      tests =[]
+      return tests unless has_qemu
+      all.each do |file_name|
+        fullname = file_name.split("/").last.split(".").first
+        order , name , stdout , exit_code = fullname.split("_")
+        method_name = "test_#{order}_#{name}"
+        input = File.read(file_name)
+        tests << method_name
+        self.send(:define_method, method_name ) do
+          out , code = run_code(input , "#{order}_#{name}")
+          assert_equal stdout , out , "Wrong stdout #{name}"
+          assert_equal exit_code , code.to_s , "Wrong exit code #{name}"
+        end
+      end
+      tests
+    end
+
+    def run_arm(input , name )
+      puts "Compiling #{name}" if ENV["TEST_ARM"] == "DEBUG"
+      linker = ::RubyX::RubyXCompiler.new({}).ruby_to_binary( input , :arm )
+      writer = Elf::ObjectWriter.new(linker)
+      writer.save "mains.o"
+      puts "Linking #{name}" if ENV["TEST_ARM"] == "DEBUG"
+      `#{@linker} -N mains.o`
+      assert_equal 0 , $?.exitstatus , "Linking #{name} failed #{$?}"
+      puts "Running #{name}" if ENV["TEST_ARM"] == "DEBUG"
+      stdout = `#{@qemu} ./a.out`
+      exit_code = $?.exitstatus
+      puts "Arm #{stdout} #{exit_code}" if ENV["TEST_ARM"] == "DEBUG"
+      return exit_code , stdout
+    end
+
+    def run_interpreter(input , name )
+      puts "Interpreting #{name}" if ENV["TEST_ARM"] == "DEBUG"
+      compiler = RubyX::RubyXCompiler.new(RubyX.default_test_options)
+      linker = compiler.ruby_to_binary(input , :interpreter)
+      interpreter = Risc::Interpreter.new(linker)
+      interpreter.start_program
+      interpreter.tick while(interpreter.instruction)
+      saved_in = interpreter.std_reg(:saved_message)
+      assert_equal Parfait::Message , interpreter.get_register(saved_in).class
+      ret = interpreter.get_register(interpreter.std_reg(:syscall_1))
+      puts "Interpret #{interpreter.stdout} #{ret}" if ENV["TEST_ARM"] == "DEBUG"
+      return ret , interpreter.stdout
+    end
+
+  end
+
 end
diff --git a/test/mains/test_assign.rb b/test/mains/test_assign.rb
new file mode 100644
index 00000000..32408742
--- /dev/null
+++ b/test/mains/test_assign.rb
@@ -0,0 +1,31 @@
+require_relative "helper"
+
+module Mains
+  class AssignTester < MiniTest::Test
+    include MainsHelper
+
+    def test_local
+      @input = as_main 'a = 15 ; return a'
+      assert_result  15 , ""
+    end
+
+    def test_plus
+      @preload = "Integer.plus"
+      @input = as_main("a = 5 + 5 ; return a")
+      assert_result 10 , ""
+    end
+
+    def test_plus2
+      @preload = "Integer.plus"
+      @input = as_main("a = 5 ;a = 5 + a ; return a")
+      assert_result 10 , ""
+    end
+
+    def test_plus3
+      @preload = "Integer.plus"
+      @input = as_main("a = 5 ;a = 5 + a ;a = a + 5; return a")
+      assert_result 15 , ""
+    end
+
+  end
+end