Externalise register allocation into own class

On the way to the register allocation

test/risc/test_allocator.rb

@@ -0,0 +1,34 @@
+require_relative "../helper"
+
+module Risc
+  class TestAllocator < MiniTest::Test
+
+    def setup
+      Parfait.boot!(Parfait.default_test_options)
+      @allocator = Allocator.new
+    end
+    def tmp_reg
+      Risc.tmp_reg(:Type)
+    end
+    def test_regs
+      assert_equal Array , @allocator.regs.class
+    end
+    def test_empty
+      assert @allocator.regs_empty?
+    end
+    def test_add_ok
+      assert_equal Array, @allocator.add_reg(tmp_reg).class
+    end
+    def test_add_fail
+      assert_raises{ @allocator.add_reg(1)}
+    end
+    def test_pop
+      @allocator.add_reg(tmp_reg)
+      assert_equal RegisterValue , @allocator.pop.class
+    end
+    def test_clear
+      @allocator.clear_regs
+      assert @allocator.regs_empty?
+    end
+  end
+end

test/risc/test_callable_compiler.rb

@@ -9,7 +9,32 @@ module Risc
     end
   end
   class TestCallableCompiler < MiniTest::Test
-
+    def setup
+      Parfait.boot!({})
+      label = SlotMachine::Label.new("hi","ho")
+      @compiler = CallableCompiler.new(FakeCallable.new  , label)
+    end
+    def test_ok
+      assert @compiler
+    end
+    def test_current
+      assert @compiler.current
+    end
+    def test_current_label
+      assert_equal Label , @compiler.current.class
+      assert_equal "ho" , @compiler.current.name
+    end
+    def test_slot
+      assert @compiler.risc_instructions
+    end
+    def test_const
+      assert_equal Array , @compiler.constants.class
+    end
+    def test_use_reg
+      @compiler.use_reg(:Type)
+    end
+  end
+  class TestFakeCallableCompiler < MiniTest::Test
     def setup
       Parfait.boot!({})
       label = SlotMachine::Label.new("hi","ho")