3 files changed, 25 insertions, 2 deletions
diff --git a/lib/east.rb b/lib/east.rb
index 1699ffc..fd5752d 100644..100755
--- a/lib/east.rb
+++ b/lib/east.rb
@@ -5,7 +5,9 @@ class East
   def turn_left
     North.new
   end
-  def forward(current_location, terrain)
-    current_location[:x] = current_location[:x]+1
+  def forward(location, terrain)
+    unless terrain.is_out_of_bounds( {:x => location[:x]+1, :y => location[:y]})
+      location[:x] = location[:x]+1
+    end
   end
 end
diff --git a/spec/east_specs.rb b/spec/east_specs.rb
new file mode 100755
index 0000000..5060956
--- /dev/null
+++ b/spec/east_specs.rb
@@ -0,0 +1,20 @@
+require 'east'
+
+describe East do
+  before(:each) do
+    @sut = East.new
+  end
+  describe "when at the edge of the terrain" do
+    describe "when moving forward" do
+      it "should just stay at the current position" do
+        @location[:x].must_equal 0
+      end
+      before do
+        terrain = fake
+        terrain.stub(:is_out_of_bounds).with({:x => -1, :y => 0}).and_return(true)
+        @location = {:x => 0, :y => 0}
+        @sut.forward(@location, terrain)
+      end
+    end
+  end
+end
diff --git a/spec/rover_specs.rb b/spec/rover_specs.rb
index f8d15f8..8c3da03 100755
--- a/spec/rover_specs.rb
+++ b/spec/rover_specs.rb
@@ -82,6 +82,7 @@ describe Rover do
     end
     describe "when driving forward" do
       before do
+        @terrain = fake
         @sut.move_forward(@terrain)
       end
       it "should increment the x coordinate on the terrain" do