[Refactor] Pull out various Kibana context mocks into separate files

- I'm creating a reusable useContext mock for shallow()ed enzyme components
+ add more documentation comments + examples

x-pack/plugins/enterprise_search/public/applications/app_search/components/engine_overview_header/engine_overview_header.test.tsx

@@ -7,7 +7,7 @@
 import React from 'react';
 
 import { EngineOverviewHeader } from '../engine_overview_header';
-import { mountWithKibanaContext } from '../../../test_utils/helpers';
+import { mountWithKibanaContext } from '../../../test_utils';
 
 describe('EngineOverviewHeader', () => {
   describe('when enterpriseSearchUrl is set', () => {

x-pack/plugins/enterprise_search/public/applications/shared/kibana_breadcrumbs/set_breadcrumbs.test.tsx

@@ -7,7 +7,7 @@
 import React from 'react';
 
 import { SetAppSearchBreadcrumbs } from '../kibana_breadcrumbs';
-import { mountWithKibanaContext } from '../../test_utils/helpers';
+import { mountWithKibanaContext } from '../../test_utils';
 
 jest.mock('./generate_breadcrumbs', () => ({
   appSearchBreadcrumbs: jest.fn(),

x-pack/plugins/enterprise_search/public/applications/shared/telemetry/send_telemetry.test.tsx

@@ -7,7 +7,7 @@
 import React from 'react';
 
 import { httpServiceMock } from 'src/core/public/mocks';
-import { mountWithKibanaContext } from '../../test_utils/helpers';
+import { mountWithKibanaContext } from '../../test_utils';
 import { sendTelemetry, SendAppSearchTelemetry } from './';
 
 describe('Shared Telemetry Helpers', () => {

x-pack/plugins/enterprise_search/public/applications/test_utils/index.ts

@@ -0,0 +1,10 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+
+export { mockKibanaContext } from './mock_kibana_context';
+export { mountWithKibanaContext } from './mount_with_context';
+
+// Note: mock_shallow_usecontext must be imported directly as a file

x-pack/plugins/enterprise_search/public/applications/test_utils/mock_kibana_context.ts

@@ -0,0 +1,17 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+
+import { httpServiceMock } from '../../../../../../src/core/public/mocks';
+
+/**
+ * A set of default Kibana context values to use across component tests.
+ * @see enterprise_search/public/index.tsx for the KibanaContext definition/import
+ */
+export const mockKibanaContext = {
+  http: httpServiceMock.createSetupContract(),
+  setBreadcrumbs: jest.fn(),
+  enterpriseSearchUrl: 'http://localhost:3002',
+};

x-pack/plugins/enterprise_search/public/applications/test_utils/mock_shallow_usecontext.ts

@@ -0,0 +1,39 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+
+/**
+ * NOTE: This variable name MUST start with 'mock*' in order for
+ * Jest to accept its use within a jest.mock()
+ */
+import { mockKibanaContext } from './mock_kibana_context';
+
+jest.mock('react', () => ({
+  ...jest.requireActual('react'),
+  useContext: jest.fn(() => mockKibanaContext),
+}));
+
+/**
+ * Example usage within a component test using shallow():
+ *
+ * import '../../../test_utils/mock_shallow_usecontext'; // Must come before React's import, adjust relative path as needed
+ *
+ * import React from 'react';
+ * import { shallow } from 'enzyme';
+ *
+ * // ... etc.
+ */
+
+/**
+ * If you need to override the default mock context values, you can do so via jest.mockImplementation:
+ *
+ * import React, { useContext } from 'react';
+ *
+ * // ... etc.
+ *
+ * it('some test', () => {
+ *   useContext.mockImplementationOnce(() => ({ enterpriseSearchUrl: 'someOverride' }));
+ * });
+ */

x-pack/plugins/enterprise_search/public/applications/test_utils/mount_with_context.tsx

@@ -0,0 +1,27 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+
+import React from 'react';
+import { mount } from 'enzyme';
+
+import { KibanaContext } from '../';
+import { mockKibanaContext } from './mock_kibana_context';
+
+/**
+ * This helper mounts a component with a set of default KibanaContext,
+ * while also allowing custom context to be passed in via a second arg
+ *
+ * Example usage:
+ *
+ * const wrapper = mountWithKibanaContext(<Component />, { enterpriseSearchUrl: 'someOverride' });
+ */
+export const mountWithKibanaContext = (node, contextProps) => {
+  return mount(
+    <KibanaContext.Provider value={{ ...mockKibanaContext, ...contextProps }}>
+      {node}
+    </KibanaContext.Provider>
+  );
+};