seperate different Position classes into own files

also tests
and have Position module keep all positions
(singletons should be at module, not class level)

test/risc/position/test_instruction_position.rb

@@ -0,0 +1,31 @@
+require_relative "../helper"
+
+module Risc
+  module Position
+    # tests that require a boot and test propagation
+    class TestPositionBasic < MiniTest::Test
+      def setup
+        Risc.machine.boot
+        @binary = Parfait::BinaryCode.new(1)
+        @label = Label.new("hi","ho")
+      end
+      def test_set_instr
+        pos = Position.set( @label , 0 , @binary)
+        assert_equal InstructionPosition , pos.class
+      end
+      def test_ins_propagates
+        @label.set_next Arm::ArmMachine.b( @label)
+        Position.set( @label , 0 , @binary)
+        assert_equal 0 , Position.get(@label.next).at
+      end
+      def test_ins_propagates_again
+        second = Arm::ArmMachine.b( @label)
+        @label.set_next(second)
+        Position.set( @label , 0 , @binary)
+        Position.set(second , 2 , @binary)
+        Position.set( @label , 0 , @binary)
+        assert_equal 0 , Position.get(@label.next).at
+      end
+    end
+  end
+end