Commit e58ab91

@@ -0,0 +1,13 @@
+class Terrain
+  def initialize(edge_of_map)
+    @map = edge_of_map
+  end
+
+  def move_forward( heading, location)
+    new_location = heading.forward(location.clone)
+    if( new_location[:x] < @map[:x] && new_location[:x] > 0 && new_location[:y] < @map[:y] && new_location[:y] > 0)
+      location[:x] = new_location[:x]
+      location[:y] = new_location[:y]
+    end
+  end
+end

@@ -1,2 +1,4 @@
 require "rspec"
 require "rspec-fakes"
+
+require_relative '../lib/terrain'

@@ -0,0 +1,72 @@
+require 'spec_helper'
+
+describe Terrain do
+  let(:sut) {Terrain.new({:x => 3, :y => 3})}
+
+  context "when moving forward" do
+    context "when the next position is to far east" do
+      it "should not let you move forward" do
+        @location[:x].should == 3
+        @location[:y].should == 0
+      end
+      before do
+        @heading = fake
+        @location = {:x => 3, :y => 0}
+        @heading.stub(:forward).with(@location).and_return({:x => 4, :y => 0})
+        sut.move_forward(@heading, @location)
+      end
+    end
+
+    context "when the next position is to far west" do
+      it "should not let you move forward" do
+        @location[:x].should == 0
+        @location[:y].should == 0
+      end
+      before do
+        @heading = fake
+        @location = {:x => 0, :y => 0}
+        @heading.stub(:forward).with(@location).and_return({:x => -1, :y => 0})
+        sut.move_forward(@heading, @location)
+      end
+    end
+
+    context "when the next position is to far north" do
+      it "should not let you move forward" do
+        @location[:x].should == 0
+        @location[:y].should == 3
+      end
+      before do
+        @heading = fake
+        @location = {:x => 0, :y => 3}
+        @heading.stub(:forward).with(@location).and_return({:x => 0, :y => 4})
+        sut.move_forward(@heading, @location)
+      end
+    end
+
+    context "when the next position is to far south" do
+      it "should not let you move forward" do
+        @location[:x].should == 0
+        @location[:y].should == 0
+      end
+      before do
+        @heading = fake
+        @location = {:x => 0, :y => 0}
+        @heading.stub(:forward).with(@location).and_return({:x => 0, :y => -1})
+        sut.move_forward(@heading, @location)
+      end
+    end
+
+    context "when the next position is just fine" do
+      it "should move position forward" do
+        @location[:x].should == 1
+        @location[:y].should == 1
+      end
+      before do
+        @heading = fake
+        @location = {:x => 0, :y => 0}
+        @heading.stub(:forward).with(@location).and_return({:x => 1, :y => 1})
+        sut.move_forward(@heading, @location)
+      end
+    end
+  end
+end

@@ -1,5 +1,4 @@
 task :default => :spec do
-
 end
 
 task :spec do