convert TestRuleResult to RTL (#53953)

.betterer.results

@@ -68,9 +68,6 @@ exports[`no enzyme tests`] = {
     "public/app/features/alerting/AlertRuleList.test.tsx:2998938420": [
       [0, 19, 13, "RegExp match", "2409514259"]
     ],
-    "public/app/features/alerting/TestRuleResult.test.tsx:2358420489": [
-      [0, 19, 13, "RegExp match", "2409514259"]
-    ],
     "public/app/features/dashboard/components/ShareModal/ShareLink.test.tsx:3716733755": [
       [0, 35, 13, "RegExp match", "2409514259"]
     ],

public/app/features/alerting/TestRuleResult.test.tsx

@@ -1,4 +1,4 @@
-import { shallow } from 'enzyme';
+import { render } from '@testing-library/react';
 import React from 'react';
 
 import { DashboardModel, PanelModel } from '../dashboard/state';
@@ -16,35 +16,20 @@ jest.mock('@grafana/runtime', () => {
   };
 });
 
-const setup = (propOverrides?: object) => {
-  const props: Props = {
-    panel: new PanelModel({ id: 1 }),
-    dashboard: new DashboardModel({ panels: [{ id: 1 }] }),
-  };
-
-  Object.assign(props, propOverrides);
-
-  const wrapper = shallow(<TestRuleResult {...props} />);
-
-  return { wrapper, instance: wrapper.instance() as TestRuleResult };
+const props: Props = {
+  panel: new PanelModel({ id: 1 }),
+  dashboard: new DashboardModel({ panels: [{ id: 1 }] }),
 };
 
-describe('Render', () => {
-  it('should render component', () => {
-    const { wrapper } = setup();
-
-    expect(wrapper).toMatchSnapshot();
+describe('TestRuleResult', () => {
+  it('should render without error', () => {
+    expect(() => render(<TestRuleResult {...props} />)).not.toThrow();
   });
-});
 
-describe('Life cycle', () => {
-  describe('component did mount', () => {
-    it('should call testRule', () => {
-      const { instance } = setup();
-      instance.testRule = jest.fn();
-      instance.componentDidMount();
+  it('should call testRule when mounting', () => {
+    jest.spyOn(TestRuleResult.prototype, 'testRule');
+    render(<TestRuleResult {...props} />);
 
-      expect(instance.testRule).toHaveBeenCalled();
-    });
+    expect(TestRuleResult.prototype.testRule).toHaveBeenCalled();
   });
 });

public/app/features/alerting/__snapshots__/TestRuleResult.test.tsx.snap

@@ -1,7 +0,0 @@
-// Jest Snapshot v1, https://goo.gl/fbAQLP
-
-exports[`Render should render component 1`] = `
-<LoadingPlaceholder
-  text="Evaluating rule"
-/>
-`;