From df51e55781efaa1fd2beca9c93fe9f409d152526 Mon Sep 17 00:00:00 2001
From: Frederic Junod <frederic.junod@camptocamp.com>
Date: Wed, 7 Jan 2015 16:48:15 +0100
Subject: [PATCH] Assert that ol.layer.Tile#getPreload is always set

---
 src/ol/layer/tilelayer.js            |  9 +++++---
 src/ol/renderer/layerrenderer.js     |  6 +----
 test/spec/ol/layer/tilelayer.test.js | 33 ++++++++++++++++++++++++++++
 3 files changed, 40 insertions(+), 8 deletions(-)
 create mode 100644 test/spec/ol/layer/tilelayer.test.js

diff --git a/src/ol/layer/tilelayer.js b/src/ol/layer/tilelayer.js
index 9aa70cf5ab..1ba0f6d1fa 100644
--- a/src/ol/layer/tilelayer.js
+++ b/src/ol/layer/tilelayer.js
@@ -30,18 +30,21 @@ ol.layer.TileProperty = {
 ol.layer.Tile = function(opt_options) {
   var options = goog.isDef(opt_options) ? opt_options : {};
   goog.base(this,  /** @type {olx.layer.LayerOptions} */ (options));
+
+  if (!goog.isDef(this.getPreload())) {
+    this.setPreload(0);
+  }
 };
 goog.inherits(ol.layer.Tile, ol.layer.Layer);
 
 
 /**
- * @return {number|undefined} The level to preload tiles up to.
+ * @return {number} The level to preload tiles up to.
  * @observable
  * @api
  */
 ol.layer.Tile.prototype.getPreload = function() {
-  return /** @type {number|undefined} */ (
-      this.get(ol.layer.TileProperty.PRELOAD));
+  return /** @type {number} */ (this.get(ol.layer.TileProperty.PRELOAD));
 };
 goog.exportProperty(
     ol.layer.Tile.prototype,
diff --git a/src/ol/renderer/layerrenderer.js b/src/ol/renderer/layerrenderer.js
index 356561bb0f..14a64db3cb 100644
--- a/src/ol/renderer/layerrenderer.js
+++ b/src/ol/renderer/layerrenderer.js
@@ -246,8 +246,7 @@ ol.renderer.Layer.prototype.snapCenterToPixel =
  * @param {ol.proj.Projection} projection Projection.
  * @param {ol.Extent} extent Extent.
  * @param {number} currentZ Current Z.
- * @param {number|undefined} preload Load low resolution tiles up to 'preload'
- *     levels.
+ * @param {number} preload Load low resolution tiles up to 'preload' levels.
  * @param {function(this: T, ol.Tile)=} opt_tileCallback Tile callback.
  * @param {T=} opt_this Object to use as `this` in `opt_tileCallback`.
  * @protected
@@ -264,9 +263,6 @@ ol.renderer.Layer.prototype.manageTilePyramid = function(
   var tileQueue = frameState.tileQueue;
   var minZoom = tileGrid.getMinZoom();
   var tile, tileRange, tileResolution, x, y, z;
-  if (!goog.isDef(preload)) {
-    preload = 0;
-  }
   for (z = currentZ; z >= minZoom; --z) {
     tileRange = tileGrid.getTileRangeForExtentAndZ(extent, z, tileRange);
     tileResolution = tileGrid.getResolution(z);
diff --git a/test/spec/ol/layer/tilelayer.test.js b/test/spec/ol/layer/tilelayer.test.js
new file mode 100644
index 0000000000..7297efa809
--- /dev/null
+++ b/test/spec/ol/layer/tilelayer.test.js
@@ -0,0 +1,33 @@
+goog.provide('ol.test.layer.Tile');
+
+describe('ol.layer.Tile', function() {
+
+  describe('constructor (defaults)', function() {
+
+    var layer;
+
+    beforeEach(function() {
+      layer = new ol.layer.Tile({
+        source: new ol.source.OSM()
+      });
+    });
+
+    afterEach(function() {
+      goog.dispose(layer);
+    });
+
+    it('creates an instance', function() {
+      expect(layer).to.be.a(ol.layer.Tile);
+    });
+
+    it('provides default preload', function() {
+      expect(layer.getPreload()).to.be(0);
+    });
+
+  });
+
+});
+
+goog.require('goog.dispose');
+goog.require('ol.layer.Tile');
+goog.require('ol.source.OSM');