参数默认值修改，优化测试

Author: songyumeng

test/leaflet/mapping/ImageMapLayerSpec.js

@@ -37,7 +37,7 @@ describe('leaflet_ImageMapLayer', () => {
         var tempOptions = {
             layersID: null,
             redirect: false,
-            transparent: null,
+            transparent: false,
             cacheEnabled: null,
             clipRegionEnabled: true,
             prjCoordSys: null,
@@ -58,7 +58,7 @@ describe('leaflet_ImageMapLayer', () => {
         expect(imageLayer).not.toBeNull();
         expect(imageLayer.options.layersID).toBeNull();
         expect(imageLayer.options.redirect).toBeFalsy();
-        expect(imageLayer.options.transparent).toBeNull();
+        expect(imageLayer.options.transparent).toBeFalsy();
         expect(imageLayer.options.cacheEnabled).toBeNull();
         expect(imageLayer.options.clipRegionEnabled).toBeTruthy();
         expect(imageLayer.options.prjCoordSys).toBeNull();
@@ -118,7 +118,7 @@ describe('leaflet_ImageMapLayer', () => {
     it('getImageUrl', () => {
         imageLayer = imageMapLayer(url).addTo(map);
         expect(imageLayer.getImageUrl()).not.toBeNull();
-        expect(imageLayer.getImageUrl()).toBe(url + "/image.png?&redirect=false&transparent=false&cacheEnabled=true&overlapDisplayed=false");
+        expect(imageLayer.getImageUrl()).toBe(url + "/image.png?&redirect=false&transparent=true&cacheEnabled=true&overlapDisplayed=false");
     });
 
     it('getImageUrl_tilePoxy', () => {
@@ -131,12 +131,12 @@ describe('leaflet_ImageMapLayer', () => {
         var oldUrl, newUrl;
         imageLayer.on('load', () => {
             oldUrl = imageLayer._currentImage._url;
-            expect(oldUrl).toBe(url + '/image.png?viewBounds=%7B%22leftBottom%22%3A%7B%22x%22%3A-19567879.241005123%2C%22y%22%3A-19567879.24100514%7D%2C%22rightTop%22%3A%7B%22x%22%3A19567879.241005123%2C%22y%22%3A19567879.241005138%7D%7D&width=500&height=500&redirect=false&transparent=false&cacheEnabled=true&overlapDisplayed=false');
+            expect(oldUrl).toBe(url + '/image.png?viewBounds=%7B%22leftBottom%22%3A%7B%22x%22%3A-19567879.241005123%2C%22y%22%3A-19567879.24100514%7D%2C%22rightTop%22%3A%7B%22x%22%3A19567879.241005123%2C%22y%22%3A19567879.241005138%7D%7D&width=500&height=500&redirect=false&transparent=true&cacheEnabled=true&overlapDisplayed=false');
             map.zoomIn();
             imageLayer.off('load');
             imageLayer.on('load', () => {
                 newUrl = imageLayer._currentImage._url;
-                expect(newUrl).toBe(url + '/image.png?viewBounds=%7B%22leftBottom%22%3A%7B%22x%22%3A-9783939.620502561%2C%22y%22%3A-9783939.620502561%7D%2C%22rightTop%22%3A%7B%22x%22%3A9783939.620502561%2C%22y%22%3A9783939.620502565%7D%7D&width=500&height=500&redirect=false&transparent=false&cacheEnabled=true&overlapDisplayed=false');
+                expect(newUrl).toBe(url + '/image.png?viewBounds=%7B%22leftBottom%22%3A%7B%22x%22%3A-9783939.620502561%2C%22y%22%3A-9783939.620502561%7D%2C%22rightTop%22%3A%7B%22x%22%3A9783939.620502561%2C%22y%22%3A9783939.620502565%7D%7D&width=500&height=500&redirect=false&transparent=true&cacheEnabled=true&overlapDisplayed=false');
                 expect(oldUrl).not.toEqual(newUrl);
                 done();
             });