test(integration-karma): simplify value evaluation throws tests

Author: gaurav-rk9

packages/@lwc/integration-karma/test/lwc-on/index.spec.js

@@ -423,7 +423,7 @@ describe('lwc:on', () => {
 
     describe('object passed to lwc:on has property whose value evaluation throws', () => {
         let element;
-        let testFn;
+        let button;
 
         let caughtError;
 
@@ -438,28 +438,24 @@ describe('lwc:on', () => {
         function setup(handlerType) {
             element = createElement('x-value-evaluation-throws', { is: ValueEvaluationThrows });
             element.handlerType = handlerType;
+            document.body.appendChild(element);
+            button = element.shadowRoot.querySelector('button');
         }
 
         it('getter that throws passed as handler', () => {
             setup('getter that throws');
-            document.body.appendChild(element);
 
             expect(caughtError.message).toBe('Uncaught Error: some error');
 
-            const button = element.shadowRoot.querySelector('button');
             expect(button).toBeNull();
         });
 
         it('LightningElement instance is passed as argument to lwc:on', () => {
             setup('LightningElement instance');
-            testFn = jasmine.createSpy('test function');
-            element.testFn = testFn;
-            document.body.appendChild(element);
 
             expect(caughtError.error instanceof TypeError).toBe(true);
             expect(caughtError.message).toBe('Uncaught TypeError: Illegal constructor');
 
-            const button = element.shadowRoot.querySelector('button');
             expect(button).toBeNull();
         });
     });

packages/@lwc/integration-karma/test/lwc-on/x/valueEvaluationThrows/valueEvaluationThrows.js

@@ -1,18 +1,8 @@
 import { LightningElement, api } from 'lwc';
 
-let testFn;
-
 export default class ValueNotFunction extends LightningElement {
     @api handlerType;
 
-    @api
-    get testFn() {
-        return testFn;
-    }
-    set testFn(val) {
-        testFn = val;
-    }
-
     get eventHandlers() {
         switch (this.handlerType) {
             case 'getter that throws':
@@ -22,11 +12,7 @@ export default class ValueNotFunction extends LightningElement {
                     },
                 };
             case 'LightningElement instance':
-                return new (class extends LightningElement {
-                    render() {
-                        testFn();
-                    }
-                })();
+                return new (class extends LightningElement {})();
             default:
                 return {};
         }