Treat /home as previous route and add tests

Include "/home" in ItemComponent's previousRoute regex so the back button is shown for home. Add unit tests to verify the back button appears for a home previous URL and that a home previous URL is prioritized over a session-stored URL (ensuring the session is updated and navigation uses the home URL).

Author: amadulhaxxani

src/app/item-page/simple/item-types/shared/item.component.spec.ts

@@ -431,6 +431,7 @@ describe('ItemComponent', () => {
 
     const searchUrl = '/search?query=test&spc.page=2';
     const browseUrl = '/browse/title?scope=0cc&bbm.page=3';
+    const homeUrl = '/home';
     const recentSubmissionsUrl = '/collections/be7b8430-77a5-4016-91c9-90863e50583a?cp.page=3';
 
     beforeEach(waitForAsync(() => {
@@ -517,6 +518,32 @@ describe('ItemComponent', () => {
         expect(val).toBeTrue();
       });
     });
+
+    it('should show back button for home', () => {
+      spyOn(mockRouteService, 'getPreviousUrl').and.returnValue(observableOf(homeUrl));
+      comp.ngOnInit();
+      comp.showBackButton.subscribe((val) => {
+        expect(val).toBeTrue();
+      });
+    });
+
+    it('should prioritize home previous url over session fallback', () => {
+      const staleSessionUrl = searchUrl;
+      const getPreviousUrlSpy = spyOn(mockRouteService, 'getPreviousUrl').and.returnValue(observableOf(homeUrl));
+      const getUrlFromSessionSpy = spyOn(mockRouteService, 'getUrlFromSession').and.returnValue(staleSessionUrl);
+      const storeUrlInSessionSpy = spyOn(mockRouteService, 'storeUrlInSession');
+
+      comp.ngOnInit();
+      comp.showBackButton.subscribe((val) => {
+        expect(val).toBeTrue();
+        expect(getPreviousUrlSpy).toHaveBeenCalled();
+        expect(getUrlFromSessionSpy).not.toHaveBeenCalled();
+        expect(storeUrlInSessionSpy).toHaveBeenCalledWith('item-previous-url', homeUrl);
+
+        comp.back();
+        expect(router.navigateByUrl).toHaveBeenCalledWith(homeUrl);
+      });
+    });
   });
 
 });

src/app/item-page/simple/item-types/shared/item.component.ts

@@ -31,7 +31,7 @@ export class ItemComponent implements OnInit {
    * This regex matches previous routes. The button is shown
    * for matching paths and hidden in other cases.
    */
-  previousRoute = /^(\/search|\/browse|\/collections|\/admin\/search|\/mydspace)/;
+  previousRoute = /^(\/home|\/search|\/browse|\/collections|\/admin\/search|\/mydspace)/;
 
   /**
    * Used to show or hide the back to results button in the view.