check bounds when facing south and moving forward.

4 files changed, 37 insertions, 2 deletions

diff --git a/lib/south.rb b/lib/south.rb
index 04851c0..5e8a434 100644..100755
--- a/lib/south.rb
+++ b/lib/south.rb
@@ -5,7 +5,9 @@ class South
   def turn_left
     East.new
   end
-  def forward(current_location, terrain)
-    current_location[:y] = current_location[:y]-1
+  def forward(location, terrain)
+    unless terrain.is_out_of_bounds({:x => location[:x], :y => location[:y]-1})
+      location[:y] = location[:y]-1
+    end
   end
 end
diff --git a/spec/rover_specs.rb b/spec/rover_specs.rb
index 52b45c3..f8d15f8 100644..100755
--- a/spec/rover_specs.rb
+++ b/spec/rover_specs.rb
@@ -55,6 +55,7 @@ describe Rover do
     end
     describe "when driving forward" do
       before do
+        @terrain = fake
         @sut.move_forward(@terrain)
       end
       it "should decrement the y coordinate on the terrain" do
diff --git a/spec/south_specs.rb b/spec/south_specs.rb
new file mode 100755
index 0000000..7d3fc33
--- /dev/null
+++ b/spec/south_specs.rb
@@ -0,0 +1,31 @@
+require 'south'

+

+describe South do

+  before do

+    @sut = South.new

+  end

+  describe "when driving forward" do

+    describe "when at the edge of the terrain" do

+      it "should not move forward" do

+        @location[:y].must_equal 1

+      end

+      before do

+        @location = {:x => 0, :y => 1}

+        @terrain = fake

+        @terrain.stub(:is_out_of_bounds).with({:x => 0, :y => 0}).and_return(true);

+        @sut.forward(@location, @terrain)

+      end

+    end

+    describe "when it is ok to move forward" do

+      it "should move forward" do

+        @location[:y].must_equal 0

+      end

+      before do

+        @location = {:x => 0, :y => 1}

+        @terrain = fake

+        @terrain.stub(:is_out_of_bounds).with({:x => 0, :y => 0}).and_return(false);

+        @sut.forward(@location, @terrain)

+      end

+    end

+  end

+end

diff --git a/spec/ts_all.rb b/spec/ts_all.rb
index b783a1e..36e285f 100644..100755
--- a/spec/ts_all.rb
+++ b/spec/ts_all.rb
@@ -8,4 +8,5 @@ require "library_specs"
 require "stack_specs"
 require "rover_specs"
 require "north_specs"
+require "south_specs"
 require "specifications/find_all_books_by_author_specs"