rename register to risc

seems to fit the layer much better as we really have a very reduced
instruction set

test/risc/test_assembler.rb

@@ -0,0 +1,43 @@
+require_relative "../helper"
+
+module Risc
+  class TestAssembler < MiniTest::Test
+
+    def setup
+      @machine = Risc.machine.boot
+    end
+    def test_no_object
+      @assembler = Assembler.new(@machine , {})
+      assert_nil @machine.translate_arm
+    end
+    def test_space
+      @assembler = Assembler.new(@machine , Collector.collect_space)
+      assert_nil @machine.translate_arm
+    end
+
+    def test_write_fails
+      @assembler = Assembler.new(@machine , {})
+      assert_raises{ @assembler.assemble} #must translate first
+    end
+    def test_assemble_no_objects
+      @assembler = Assembler.new(@machine , {})
+      assert_nil @machine.translate_arm
+      assert @assembler.assemble
+    end
+
+    def test_translate_space
+      @assembler = Assembler.new(@machine , Collector.collect_space)
+      assert_nil @machine.translate_arm
+    end
+    def test_assemble_space
+      @assembler = Assembler.new(@machine , Collector.collect_space)
+      assert_nil @machine.translate_arm
+      assert @assembler.assemble
+    end
+    def test_write_space
+      @assembler = Assembler.new(@machine , Collector.collect_space)
+      assert_nil @machine.translate_arm
+      assert @assembler.write_as_string
+    end
+  end
+end