[ACS-11325] remove chevron button from tab order in adf-tree (#12041)

* [ACS-11325] remove chevron button from tab order in adf-tree

* [ACS-11325] add unit tests

lib/content-services/src/lib/tree/components/tree.component.html

@@ -58,7 +58,9 @@
                         *ngIf="node.hasChildren"
                         class="adf-tree-expand-collapse-button"
                         mat-icon-button
-                        matTreeNodeToggle
+                        tabindex="-1"
+                        aria-hidden="true"
+                        (click)="expandCollapseNode(node); $event.stopPropagation()"
                     >
                         <mat-progress-spinner
                                 mode="indeterminate"

lib/content-services/src/lib/tree/components/tree.component.spec.ts

@@ -213,6 +213,26 @@ describe('TreeComponent', () => {
         expect(expandSpy).toHaveBeenCalledWith(component.treeService.treeNodes[0], treeNodesMockExpanded);
     });
 
+    it('should call expandCollapseNode once when chevron is clicked', () => {
+        component.refreshTree();
+        fixture.detectChanges();
+        component.treeService.treeNodes = Array.from(treeNodesMock);
+        component.treeService.treeNodes[0].isLoading = false;
+        fixture.detectChanges();
+        const expandCollapseNodeSpy = spyOn(component, 'expandCollapseNode').and.callThrough();
+        clickExpandCollapseBtn(component.treeService.treeNodes[0].id);
+        expect(expandCollapseNodeSpy).toHaveBeenCalledOnceWith(component.treeService.treeNodes[0]);
+    });
+
+    it('should not trigger node selection when chevron is clicked and selectableNodes is true', () => {
+        component.selectableNodes = true;
+        component.refreshTree();
+        fixture.detectChanges();
+        const onNodeSelectedSpy = spyOn(component, 'onNodeSelected');
+        clickExpandCollapseBtn(component.treeService.treeNodes[0].id);
+        expect(onNodeSelectedSpy).not.toHaveBeenCalled();
+    });
+
     it('should call collapseNode on TreeService when collapsing node by clicking at node label and node has children', () => {
         component.refreshTree();
         fixture.detectChanges();