start with some slot definition tests

test/mom/instruction/helper.rb

@@ -0,0 +1,13 @@
+require_relative '../helper'
+
+module Mom
+  class CompilerMock
+    def use_reg( type )
+      Risc.tmp_reg(type , nil)
+    end
+    def add_constant(c)
+    end
+  end
+  class InstructionMock < Instruction
+  end
+end