test(dropdown): use provided in open method target

Author: wnvko

projects/igniteui-angular/src/lib/drop-down/drop-down.component.spec.ts

@@ -256,7 +256,6 @@ describe('IgxDropDown ', () => {
                 expect(positionStrategy.settings.horizontalDirection).toBe(HorizontalAlignment.Right);
                 expect(positionStrategy.settings.verticalDirection).toBe(VerticalAlignment.Bottom);
             });
-
             it('should apply custom overlay settings if provided', () => {
                 const toggle: IgxToggleDirective = (dropdown as any).toggleDirective;
                 const customOverlaySettings: OverlaySettings = {
@@ -1266,6 +1265,31 @@ describe('IgxDropDown ', () => {
                 expect(dropdown.closing.emit).toHaveBeenCalledTimes(3);
                 expect(dropdown.closed.emit).toHaveBeenCalledTimes(3);
             }));
+            fit('#15137 - should bind to custom target if provided', fakeAsync(() => {
+                const input = fixture.debugElement.query(By.css('input'));
+                dropdown.open({ target: input.nativeElement });
+                tick();
+                fixture.detectChanges();
+
+                const dropdownItems = fixture.debugElement.queryAll(By.css(`.${CSS_CLASS_ITEM}`));
+                expect(dropdownItems).not.toBeUndefined();
+
+                const inputRect = input.nativeElement.getBoundingClientRect();
+                let dropdownRect = dropdownItems[0].nativeElement.getBoundingClientRect();
+                expect(dropdownRect.left).toBe(inputRect.left);
+                expect(dropdownRect.top).toBe(inputRect.bottom);
+
+                dropdown.close();
+                tick();
+                fixture.detectChanges();
+                dropdown.open();
+                tick();
+                fixture.detectChanges();
+
+                dropdownRect = dropdownItems[0].nativeElement.getBoundingClientRect();
+                expect(dropdownRect.left).toBe(0);
+                expect(dropdownRect.top).toBe(0);
+            }));
         });
     });
 });
@@ -1341,7 +1365,6 @@ class DoubleIgxDropDownComponent implements OnInit {
         }
     }
 }
-
 @Component({
     template: `
     <input (click)="toggleDropDown()">