fix tests, and add new ones

tests/Layer/Grid.html

@@ -21,14 +21,13 @@
 
 
     function test_Layer_Grid_constructor (t) {
-        t.plan( 6 );
+        t.plan( 5 );
                        
         layer = new OpenLayers.Layer.Grid(name, url, params, null);
         t.ok( layer instanceof OpenLayers.Layer.Grid, "returns OpenLayers.Layer.Grid object" );
         t.eq( layer.buffer, 0, "buffer default is 0");
         t.eq( layer.ratio, 1.5, "ratio default is 1.5");
         t.eq( layer.numLoadingTiles, 0, "numLoadingTiles starts at 0");
-        t.eq( layer.backBufferData, {}, "backBufferData set to empty object");
 
         var obj = {};
         var func = function() {};
@@ -50,7 +49,7 @@
     }
 
     function test_Layer_Grid_clearTiles (t) {
-        t.plan(3);
+        t.plan(4);
 
         var map = new OpenLayers.Map('map');
         layer = new OpenLayers.Layer.WMS(name, url, params);
@@ -86,6 +85,7 @@
         t.ok( layer.grid != null, "layer.grid does not get nullified" );
         t.eq(tilesDeleted, numTiles, "all tiles destroy()ed properly");
         t.ok(allTilesUnhooked, "all tiles unhooked before being destroyed");
+        t.eq(layer.gridResolution, null, "gridResolution set to null");
 
         OpenLayers.Tile.Image.prototype.destroy =
             OpenLayers.Tile.Image.prototype._destroy;
@@ -168,6 +168,7 @@
         var map = new OpenLayers.Map('map');
         layer = new OpenLayers.Layer.WMS(name, url, params);
         layer.destroy = function() {}; //we're going to do funky things with the grid
+        layer.applyBackBuffer = function() {}; // backbuffering isn't under test here
         map.addLayer(layer);
 
     //make sure null bounds doesnt cause script error. 
@@ -391,6 +392,8 @@
             getLayerPxFromLonLat: function(ul) {
                 t.ok(ul.equals(desiredUL), "correct ul passed to translation");
                 return translatedPX;        
+            },
+            getResolution: function() {
             }
         }
 
@@ -588,7 +591,7 @@
 
     function test_Layer_Grid_destroy (t) {
 
-        t.plan( 9 );
+        t.plan( 10 );
 
         var map = new OpenLayers.Map('map');
         layer = new OpenLayers.Layer.Grid(name, url, params);
@@ -605,17 +608,21 @@
         map.setCenter(new OpenLayers.LonLat(0,0), 10);
         map.setCenter(new OpenLayers.LonLat(1,1));
 
-         
         //grab a reference to one of the tiles
         var tile = layer.grid[1][1];        
         t.eq( tile.imgDiv.className, "olTileImage", "Tile has an image" ); 
 
+        // add a fake back buffer to the layer
+        var backBuffer = document.createElement('div');
+        layer.backBuffer = backBuffer
+        layer.div.appendChild(backBuffer);
+
         layer.destroy();
         t.eq( tile.imgDiv, null, "Tile destroyed" ); 
         t.eq( layer.timerId, null, "Tile loading timeout cleared");
-        
         t.ok( layer.grid == null, "tiles appropriately destroyed")
-        t.eq( layer.backBufferData, null, "backBufferData set to null");
+        t.ok( backBuffer.parentNode === layer.div, "back buffer removed");
+        t.eq( layer.backBuffer, null, "backBuffer set not null in the layer");
 
         // destroy after remove from map
         layer = new OpenLayers.Layer.WMS(name, url, params);
@@ -782,23 +789,20 @@
         // initial resolution is 0.025
         resolution = undefined;
         map.setCenter(new OpenLayers.LonLat(0, 0), 2);
-        t.eq(resolution, undefined,
+        t.eq(resolution, 0.025,
              'applyBackBuffer not called on first moveTo');
-        layer.backBufferData.resolution = 0.025;
 
         // move to (-90, 45)
         resolution = undefined;
         map.setCenter(new OpenLayers.LonLat(-90, 45));
         t.eq(resolution, 0.025,
              'applyBackBuffer called when map is moved');
-        layer.backBufferData.resolution = 0.025;
 
         // change to resolution 1
         resolution = undefined;
         map.zoomTo(0);
         t.eq(resolution, 1,
              'applyBackBuffer called when map is zoomed out');
-        layer.backBufferData.resolution = 1;
 
         // change to resolution 0.5
         resolution = undefined;
@@ -828,23 +832,20 @@
         // initial resolution is 0.025
         resolution = undefined;
         map.setCenter(new OpenLayers.LonLat(0, 0), 2);
-        t.eq(resolution, undefined,
+        t.eq(resolution, 0.025,
              'applyBackBuffer not called on first moveTo');
-        layer.backBufferData.resolution = 0.025;
 
         // move to (-90, 45)
         resolution = undefined;
         map.setCenter(new OpenLayers.LonLat(-90, 45));
         t.eq(resolution, undefined,
              'applyBackBuffer not called when map is moved');
-        layer.backBufferData.resolution = 0.025;
 
         // change to resolution 1
         resolution = undefined;
         map.zoomTo(0);
         t.eq(resolution, 1,
              'applyBackBuffer called when map is zoomed out');
-        layer.backBufferData.resolution = 1;
 
         // change to resolution 0.5
         map.zoomTo(1);
@@ -853,6 +854,7 @@
 
         map.destroy();
     }
+
     function test_transformDiv(t) {
 
         t.plan(8);
@@ -933,7 +935,8 @@
             backBuffer = document.createElement('div');
             return backBuffer;
         };
-        layer.backBufferData = {resolution: 32, lonlat: map.getCenter()};
+        layer.gridResolution = 32;
+        layer.grid[0][0].bounds = new OpenLayers.Bounds(0, 1, 1, 0);
         layer.applyBackBuffer(2);
         t.ok(layer.backBuffer === backBuffer,
              'back buffer set in layer');
@@ -953,7 +956,8 @@
             backBuffer = document.createElement('div');
             return backBuffer;
         };
-        layer.backBufferData = {resolution: 32, lonlat: map.getCenter()};
+        layer.gridResolution = 32;
+        layer.grid[0][0].bounds = new OpenLayers.Bounds(0, 1, 1, 0);
         map.layerContainerDiv.style.left = '20px';
         map.layerContainerDiv.style.top = '-20px';
         layer.applyBackBuffer(2);
@@ -974,7 +978,7 @@
     }
 
     function test_createBackBuffer(t) {
-        t.plan(6);
+        t.plan(7);
 
         var map = new OpenLayers.Map('map');
         var layer = new OpenLayers.Layer.WMS('', '', {}, {
@@ -991,8 +995,10 @@
             return;
         };
         backBuffer = layer.createBackBuffer();
-        t.eq(backBuffer, undefined,
+        t.ok(backBuffer != undefined,
-             'createBackBuffer returns undefined if createBackBuffer returns undefined');
+             'createBackBuffer returns a back buffer');
+        t.eq(backBuffer.childNodes.length, 0,
+             'returned back buffer has no child nodes');
 
         OpenLayers.Tile.Image.prototype.createBackBuffer = function() {
             return document.createElement('div');
@@ -1013,22 +1019,25 @@
         OpenLayers.Tile.Image.prototype.createBackBuffer = createBackBuffer;
     }
 
-    function test_updateBackBufferData(t) {
+    function test_removeBackBuffer(t) {
-        t.plan(1);
+        t.plan(3);
 
-        var map = new OpenLayers.Map('map', {
+        var map = new OpenLayers.Map('map');
-            resolutions: [32, 16]
+        var layer = new OpenLayers.Layer.WMS('', '', {}, {isBaseLayer: true});
-        });
-        var layer = new OpenLayers.Layer.WMS('', '', {}, {
-            isBaseLayer: true
-        });
         map.addLayer(layer);
-        map.setCenter(new OpenLayers.LonLat(0, 0), 0);
 
-        layer.backBufferData = {};
+        // add a fake back buffer
-        layer.updateBackBufferData();
+        var backBuffer = document.createElement('div');
-        t.eq(layer.backBufferData.resolution, 32,
+        layer.backBuffer = backBuffer;
-             'backBufferData has correct resolution');
+        layer.div.appendChild(backBuffer);
+        layer.backBufferResolution = 32;
+
+        layer.removeBackBuffer();
+        t.eq(layer.backBuffer, null, 'backBuffer set to null in layer');
+        t.eq(layer.backBufferResolution, null,
+             'backBufferResolution set to null in layer');
+        t.ok(backBuffer.parentNode !== layer.div,
+             'back buffer removed from layer');
 
         map.destroy();
     }
@@ -1054,11 +1063,6 @@
         map.addLayer(layer);
         map.setCenter(new OpenLayers.LonLat(0, 0), 0);
 
-        // pretend the image has been loaded
-        layer.updateBackBufferData();
-        layer.grid[0][0].isLoading = false; // this is to be able to create
-                                            // a back buffer
-
         // move
         map.setCenter(new OpenLayers.LonLat(10, 10));
         t.ok(layer.backBuffer && layer.backBuffer.parentNode === layer.div,
@@ -1073,7 +1077,7 @@
     }
 
     function test_backbuffer_scaled_layer(t) {
-        t.plan(15);
+        t.plan(12);
 
         //
         // set up
@@ -1090,14 +1094,20 @@
         );
         
         layer.serverResolutions = [32, 16, 8];
-        layer.createBackBuffer = function() {
-            return document.createElement('div');
-        };
 
         map.addLayer(layer);
         map.setCenter(new OpenLayers.LonLat(0, 0), 2);
 
-        layer.updateBackBufferData();
+        layer.createBackBuffer = function() {
+            return document.createElement('div');
+        };
+
+        // we want to control when the back buffer is removed
+        var removeBackBuffer = OpenLayers.Function.bind(
+                layer.removeBackBuffer, layer);
+        layer.removeBackBuffer = function() {};
+
+       // layer.updateBackBufferData();
 
         //
         // test
@@ -1105,65 +1115,63 @@
 
         // change resolution from 8 to 4
         map.zoomTo(3);
-        t.ok(layer.backBuffer == undefined,
+        t.eq(layer.backBuffer.style.width, '100%',
-            '[8->4] back buffer not applied');
+            '[8->4] back buffer not scaled');
-        layer.updateBackBufferData();
+        removeBackBuffer();
 
         // change resolution from 8 to 2
-        map.zoomTo(2); layer.updateBackBufferData(); map.zoomTo(4);
+        map.zoomTo(2); removeBackBuffer(); map.zoomTo(4);
-        t.ok(layer.backBuffer == undefined,
+        t.eq(layer.backBuffer.style.width, '100%',
-            '[8->2] back buffer not applies');
+            '[8->2] back buffer not scaled');
-        layer.updateBackBufferData();
+        removeBackBuffer();
 
         // change resolution from 16 to 4
-        map.zoomTo(1); layer.updateBackBufferData(); map.zoomTo(3);
+        map.zoomTo(1); removeBackBuffer(); map.zoomTo(3);
-        t.ok(layer.backBuffer != undefined,
-             '[16->4] back buffer applied');
         t.eq(layer.backBuffer.style.width, '200%',
              '[16->4] back buffer width is as expected');
         t.eq(layer.backBuffer.style.width, '200%',
              '[16->4] back buffer height is as expected');
-        layer.updateBackBufferData();
+        removeBackBuffer();
 
         // change resolution from 32 to 1
-        map.zoomTo(0); layer.updateBackBufferData(); map.zoomTo(5);
+        map.zoomTo(0); removeBackBuffer(); map.zoomTo(5);
-        t.ok(layer.backBuffer != undefined,
-             '[32->1] back buffer applied');
         t.eq(layer.backBuffer.style.width, '400%',
              '[32->1] back buffer width is as expected');
         t.eq(layer.backBuffer.style.width, '400%',
              '[32->1] back buffer height is as expected');
-        layer.updateBackBufferData();
+        removeBackBuffer();
 
         // change resolution from 4 to 2
-        map.zoomTo(3); layer.updateBackBufferData(); map.zoomTo(4);
+        map.zoomTo(3); removeBackBuffer(); map.zoomTo(4);
-        t.ok(layer.backBuffer == undefined,
+        t.eq(layer.backBuffer.style.width, '100%',
-            '[4->2] back buffer not applied');
+            '[4->2] back buffer not scaled');
-        layer.updateBackBufferData();
+        removeBackBuffer();
 
         // change resolution from 4 to 1
-        map.zoomTo(3); layer.updateBackBufferData(); map.zoomTo(5);
+        map.zoomTo(3); removeBackBuffer(); map.zoomTo(5);
-        t.ok(layer.backBuffer == undefined,
+        t.eq(layer.backBuffer.style.width, '100%',
-            '[4->1] back buffer not applied');
+            '[4->1] back buffer not scaled');
+        removeBackBuffer();
 
         // change resolution from 1 to 4
-        map.zoomTo(5); layer.updateBackBufferData(); map.zoomTo(3);
+        map.zoomTo(5); removeBackBuffer(); map.zoomTo(3);
-        t.ok(layer.backBuffer == undefined,
+        t.eq(layer.backBuffer.style.width, '100%',
-             '[1->4] back buffer not applied');
+            '[1->4] back buffer not scaled');
+        removeBackBuffer();
 
         // change resolution from 4 to 8
-        map.zoomTo(3); layer.updateBackBufferData(); map.zoomTo(2);
+        map.zoomTo(3); removeBackBuffer(); map.zoomTo(2);
-        t.ok(layer.backBuffer == undefined,
+        t.eq(layer.backBuffer.style.width, '100%',
-             '[4->8] back buffer not applied');
+            '[4->8] back buffer not scaled');
+        removeBackBuffer();
 
         // change resolution from 4 to 16
-        map.zoomTo(3); layer.updateBackBufferData(); map.zoomTo(1);
+        map.zoomTo(3); removeBackBuffer(); map.zoomTo(1);
-        t.ok(layer.backBuffer != undefined,
-             '[4->16] back buffer applied');
         t.eq(layer.backBuffer.style.width, '50%',
              '[4->16] back buffer width is as expected');
         t.eq(layer.backBuffer.style.width, '50%',
              '[4->16] back buffer height is as expected');
+        removeBackBuffer();
 
         //
         // tear down