feat(accordion): allow custom panel class

- add support for custom panel class

Closes #4242
Fixes #3968

src/accordion/accordion.js

@@ -80,6 +80,7 @@ angular.module('ui.bootstrap.accordion', ['ui.bootstrap.collapse'])
       accordionCtrl.addGroup(scope);
 
       scope.openClass = attrs.openClass || 'panel-open';
+      scope.panelClass = attrs.panelClass;
       scope.$watch('isOpen', function(value) {
         element.toggleClass(scope.openClass, value);
         if (value) {

src/accordion/docs/readme.md

@@ -13,5 +13,7 @@ The body of each accordion group is transcluded in to the body of the collapsibl
 
 ### Accordion Group Settings ###
 
+  * `panel-class` (Defaults: `panel-default`) :
+    Add ability to use Bootstrap's contextual panel classes (panel-primary, panel-success, panel-info, etc...) or your own.  This must be a string.
   * `template-url` (Defaults: `template/accordion/accordion-group.html`) :
     Add ability to override the template url used. Note that this must be a string

src/accordion/test/accordion.spec.js

@@ -515,7 +515,6 @@ describe('accordion', function() {
       });
     });
 
-
     describe('accordion-heading attribute, with repeating accordion-groups', function() {
       it('should clone the accordion-heading for each group', function() {
         element = $compile('<accordion><accordion-group ng-repeat="x in [1,2,3]"><div accordion-heading>{{x}}</div></accordion-group></accordion>')(scope);
@@ -528,5 +527,26 @@ describe('accordion', function() {
       });
     });
 
+    describe('accordion group panel class - #3968', function() {
+      it('should use the default value when panel class is falsy', function() {
+        element = $compile('<accordion><accordion-group heading="Heading">Content</accordion-group></accordion>')(scope);
+        scope.$digest();
+        groups = element.find('.panel');
+        expect(groups.eq(0)).toHaveClass('panel-default');
+
+        element = $compile('<accordion><accordion-group heading="Heading" panel-class="">Content</accordion-group></accordion>')(scope);
+        scope.$digest();
+        groups = element.find('.panel');
+        expect(groups.eq(0)).toHaveClass('panel-default');
+      });
+
+      it('should use the specified value when not falsy', function() {
+        element = $compile('<accordion><accordion-group heading="Heading" panel-class="custom-class">Content</accordion-group></accordion>')(scope);
+        scope.$digest();
+        groups = element.find('.panel');
+        expect(groups.eq(0)).toHaveClass('custom-class');
+        expect(groups.eq(0)).not.toHaveClass('panel-default');
+      });
+    });
   });
 });

template/accordion/accordion-group.html

@@ -1,4 +1,4 @@
-<div class="panel panel-default">
+<div class="panel {{panelClass || 'panel-default'}}">
   <div class="panel-heading">
     <h4 class="panel-title">
       <a href tabindex="0" class="accordion-toggle" ng-click="toggleOpen()" accordion-transclude="heading"><span ng-class="{'text-muted': isDisabled}">{{heading}}</span></a>