[Cases] Fix create case submit button flaky test (#174570)

## Summary

Fixes: #174376

Successful runs:
https://buildkite.com/elastic/kibana-pull-request/builds?branch=cnasikas%3Afix_174376

### Checklist

- [x] [Unit or functional
tests](https://www.elastic.co/guide/en/kibana/master/development-tests.html)
were updated or added to match the most common scenarios


### For maintainers

- [x] This was checked for breaking API changes and was [labeled
appropriately](https://www.elastic.co/guide/en/kibana/master/contributing.html#kibana-release-notes-process)

x-pack/plugins/cases/public/components/create/submit_button.test.tsx

@@ -6,81 +6,55 @@
  */
 
 import React from 'react';
-import { mount } from 'enzyme';
-import { waitFor } from '@testing-library/react';
+import { waitFor, screen } from '@testing-library/react';
 
-import { useForm, Form } from '@kbn/es-ui-shared-plugin/static/forms/hook_form_lib';
 import { SubmitCaseButton } from './submit_button';
-import type { FormProps } from './schema';
-import { schema } from './schema';
+import type { AppMockRenderer } from '../../common/mock';
+import { createAppMockRenderer } from '../../common/mock';
+import { FormTestComponent } from '../../common/test_utils';
+import userEvent from '@testing-library/user-event';
 
-// FLAKY: https://github.com/elastic/kibana/issues/174376
-describe.skip('SubmitCaseButton', () => {
+describe('SubmitCaseButton', () => {
+  let appMockRender: AppMockRenderer;
   const onSubmit = jest.fn();
 
-  const MockHookWrapperComponent: React.FC = ({ children }) => {
-    const { form } = useForm<FormProps>({
-      defaultValue: { title: 'My title' },
-      schema: {
-        title: schema.title,
-      },
-      onSubmit,
-    });
-
-    return <Form form={form}>{children}</Form>;
-  };
-
   beforeEach(() => {
     jest.clearAllMocks();
+    appMockRender = createAppMockRenderer();
   });
 
-  it('it renders', async () => {
-    const wrapper = mount(
-      <MockHookWrapperComponent>
+  it('renders', async () => {
+    appMockRender.render(
+      <FormTestComponent onSubmit={onSubmit}>
         <SubmitCaseButton />
-      </MockHookWrapperComponent>
+      </FormTestComponent>
     );
 
-    expect(wrapper.find(`[data-test-subj="create-case-submit"]`).exists()).toBeTruthy();
+    expect(await screen.findByTestId('create-case-submit')).toBeInTheDocument();
   });
 
-  it('it submits', async () => {
-    const wrapper = mount(
-      <MockHookWrapperComponent>
+  it('submits', async () => {
+    appMockRender.render(
+      <FormTestComponent onSubmit={onSubmit}>
         <SubmitCaseButton />
-      </MockHookWrapperComponent>
+      </FormTestComponent>
     );
-    wrapper.find(`button[data-test-subj="create-case-submit"]`).first().simulate('click');
-    await waitFor(() => expect(onSubmit).toBeCalled());
-  });
 
-  it('it disables when submitting', async () => {
-    const wrapper = mount(
-      <MockHookWrapperComponent>
-        <SubmitCaseButton />
-      </MockHookWrapperComponent>
-    );
+    userEvent.click(await screen.findByTestId('create-case-submit'));
 
-    wrapper.find(`button[data-test-subj="create-case-submit"]`).first().simulate('click');
-    await waitFor(() =>
-      expect(
-        wrapper.find(`[data-test-subj="create-case-submit"]`).first().prop('isDisabled')
-      ).toBeTruthy()
-    );
+    await waitFor(() => expect(onSubmit).toBeCalled());
   });
 
-  it('it is loading when submitting', async () => {
-    const wrapper = mount(
-      <MockHookWrapperComponent>
+  it('disables when submitting', async () => {
+    appMockRender.render(
+      <FormTestComponent onSubmit={onSubmit}>
         <SubmitCaseButton />
-      </MockHookWrapperComponent>
+      </FormTestComponent>
     );
 
-    wrapper.find(`button[data-test-subj="create-case-submit"]`).first().simulate('click');
-    await waitFor(() =>
-      expect(
-        wrapper.find(`[data-test-subj="create-case-submit"]`).first().prop('isLoading')
-      ).toBeTruthy()
-    );
+    const button = await screen.findByTestId('create-case-submit');
+    userEvent.click(button);
+
+    await waitFor(() => expect(button).toBeDisabled());
   });
 });