Make the resolution constraint configurable through map options

test/spec/ol/mapoptions.test.js

@@ -0,0 +1,54 @@
+goog.require('ol.MapOptions');
+
+describe('ol.MapOptions', function() {
+
+  describe('create constraints', function() {
+
+    describe('create resolution constraint', function() {
+
+      describe('with no options', function() {
+        it('gives a correct resolution constraint function', function() {
+          var options = {};
+          var fn = ol.MapOptions.createConstraints_(options).resolution;
+          expect(fn(156543.03392804097, 0))
+              .toRoughlyEqual(156543.03392804097, 1e-9);
+          expect(fn(78271.51696402048, 0))
+              .toRoughlyEqual(78271.51696402048, 1e-10);
+        });
+      });
+
+      describe('with maxResolution, numZoomLevels, and zoomFactor options',
+          function() {
+        it('gives a correct resolution constraint function', function() {
+          var options = {
+            maxResolution: 81,
+            numZoomLevels: 4,
+            zoomFactor: 3
+          };
+          var fn = ol.MapOptions.createConstraints_(options).resolution;
+          expect(fn(82, 0)).toEqual(81);
+          expect(fn(81, 0)).toEqual(81);
+          expect(fn(27, 0)).toEqual(27);
+          expect(fn(9, 0)).toEqual(9);
+          expect(fn(3, 0)).toEqual(3);
+          expect(fn(2, 0)).toEqual(3);
+        });
+      });
+
+      describe('with resolutions', function() {
+        it('gives a correct resolution constraint function', function() {
+          var options = {
+            resolutions: [97, 76, 65, 54, 0.45]
+          };
+          var fn = ol.MapOptions.createConstraints_(options).resolution;
+          expect(fn(97, 0), 97);
+          expect(fn(76, 0), 76);
+          expect(fn(65, 0), 65);
+          expect(fn(54, 0), 54);
+          expect(fn(0.45, 0), 0.45);
+        });
+      });
+
+    });
+  });
+});