Fix JS test failures due to browser discrepancies

Firefox and Chromium return different values when evaluating
"background-image", absolute URL vs relative URL.

This fix adjusts the TestUtil to normalize the URL to absolute because
the purpose of the test is just to check that the correct target image
was set.

core/js/tests/specHelper.js

@@ -127,7 +127,7 @@ window.isPhantom = /phantom/i.test(navigator.userAgent);
 		/**
 		 * Returns the image URL set on the given element
 		 * @param $el element
-		 * @return {String} image URL
+		 * @return {String} absolute image URL
 		 */
 		getImageUrl: function($el) {
 			// might be slightly different cross-browser
@@ -136,7 +136,13 @@ window.isPhantom = /phantom/i.test(navigator.userAgent);
 			if (!r) {
 				return url;
 			}
-			return r[1];
+			url = r[1];
+
+			// some browsers return this as relative URL, others as absolute
+			if (!url.startsWith(OC.getProtocol() + '://')) {
+				return this.buildAbsoluteUrl(url);
+			}
+			return url;
 		},
 		buildAbsoluteUrl: function(relativeUrl) {
 			return window.location.protocol + '//' + window.location.host + relativeUrl;

core/js/tests/specs/shareSpec.js

@@ -100,7 +100,7 @@ describe('OC.Share tests', function() {
 		describe('displaying the folder icon', function() {
 			function checkIcon(expectedImage) {
 				var imageUrl = OC.TestUtil.getImageUrl($file.find('.filename .thumbnail'));
-				expectedIcon = OC.TestUtil.buildAbsoluteUrl(OC.imagePath('core', expectedImage));
+				var expectedIcon = OC.TestUtil.buildAbsoluteUrl(OC.imagePath('core', expectedImage));
 				expect(imageUrl).toEqual(expectedIcon);
 			}