make tanks collide with water

spec/TankSpec.js

@@ -127,6 +127,16 @@ describe("Tank", function () {
     expect(tank.resolveCollisionWithSprite).toHaveBeenCalledWith(base);
   });
 
+  it("should resolve collision when collides with water", function () {
+    spyOn(tank, 'resolveCollisionWithSprite');
+    var water = new Water(eventManager);
+    tank.notify({
+      'name': CollisionDetector.Event.COLLISION,
+      'initiator': tank,
+      'sprite': water});
+    expect(tank.resolveCollisionWithSprite).toHaveBeenCalledWith(water);
+  });
+
   describe("collision with a tank", function () {
     it("normal tank", function () {
       spyOn(tank, 'resolveCollisionWithSprite');

src/Tank.js

@@ -166,7 +166,7 @@ Tank.prototype.notify = function (event) {
   if (event.name == Bullet.Event.DESTROYED && event.tank == this) {
     this._bullets--;
   }
-  else if (this._wallCollision(event) || this._tankCollision(event) || this._baseCollision(event)) {
+  else if (this._wallCollision(event) || this._tankCollision(event) || this._baseCollision(event) || this._waterCollision(event)) {
     this.resolveCollisionWithSprite(event.sprite);
   }
   else if (this._bulletCollision(event) && this.canBeDestroyed()) {
@@ -402,6 +402,12 @@ Tank.prototype._baseCollision = function (event) {
     event.sprite instanceof Base;
 };
 
+Tank.prototype._waterCollision = function (event) {
+  return event.name == CollisionDetector.Event.COLLISION &&
+    event.initiator === this &&
+    event.sprite instanceof Water;
+};
+
 Tank.prototype._tankCollision = function (event) {
   return event.name == CollisionDetector.Event.COLLISION &&
     event.initiator === this &&

src/Water.js

@@ -1,6 +1,8 @@
 function Water(eventManager) {
   Sprite.call(this, eventManager);
   this._animation = new Animation([1,2], 30, true);
+  this._w = Globals.UNIT_SIZE;
+  this._h = Globals.UNIT_SIZE;
 }
 
 Water.subclass(Sprite);