Get closest resolution.

test/spec/ol/renderer/TileLayerRenderer.test.js

@@ -15,5 +15,61 @@ describe("ol.renderer.TileLayerRenderer", function() {
         expect(ol.renderer.TileLayerRenderer.canRender(layer)).toBe(false);
     });
     
+    describe("getPreferredResAndZ_", function() {
+        var layer = new ol.layer.TileLayer();
+        var resolutions = [100, 80, 50, 10, 1, 0.1];
+        layer.setResolutions(resolutions);
+        
+        var container = document.createElement("div");
+        var renderer = new ol.renderer.TileLayerRenderer(container, layer);
+
+        it("gets the max resolution", function() {
+            var pair = renderer.getPreferredResAndZ_(100);
+            expect(pair[0]).toBe(100);
+            expect(pair[1]).toBe(0);
+        });
+
+        it("gets the min resolution", function() {
+            var pair = renderer.getPreferredResAndZ_(0.1);
+            expect(pair[0]).toBe(0.1);
+            expect(pair[1]).toBe(5);
+        });
+
+        it("gets the max when bigger", function() {
+            var pair = renderer.getPreferredResAndZ_(200);
+            expect(pair[0]).toBe(100);
+            expect(pair[1]).toBe(0);
+        });
+
+        it("gets the min when smaller", function() {
+            var pair = renderer.getPreferredResAndZ_(0.01);
+            expect(pair[0]).toBe(0.1);
+            expect(pair[1]).toBe(5);
+        });
+
+        it("gets the first when in the middle", function() {
+            var pair = renderer.getPreferredResAndZ_(90);
+            expect(pair[0]).toBe(100);
+            expect(pair[1]).toBe(0);
+        });
+
+        it("gets the closer when elsewhere", function() {
+            var pair = renderer.getPreferredResAndZ_(89);
+            expect(pair[0]).toBe(80);
+            expect(pair[1]).toBe(1);
+            
+            pair = renderer.getPreferredResAndZ_(49);
+            expect(pair[0]).toBe(50);
+            expect(pair[1]).toBe(2);
+
+            pair = renderer.getPreferredResAndZ_(0.5);
+            expect(pair[0]).toBe(0.1);
+            expect(pair[1]).toBe(5);
+        });
+        
+    });
+    
+    
+    
 });