add jest test for IncompleteResultsModal component

src/plugins/data/public/incomplete_results_modal/incomplete_results_modal.test.tsx

@@ -0,0 +1,68 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0 and the Server Side Public License, v 1; you may not use this file except
+ * in compliance with, at your election, the Elastic License 2.0 or the Server
+ * Side Public License, v 1.
+ */
+
+import React from 'react';
+import { shallow } from 'enzyme';
+import type * as estypes from '@elastic/elasticsearch/lib/api/typesWithBodyKey';
+import type { SearchResponseIncompleteWarning } from '../search';
+import { IncompleteResultsModal } from './incomplete_results_modal';
+
+describe('IncompleteResultsModal', () => {
+  test('should render shard failures', () => {
+    const component = shallow(
+      <IncompleteResultsModal
+        warning={{} as unknown as SearchResponseIncompleteWarning}
+        request={{}}
+        response={{
+          _shards: {
+            total: 4,
+            successful: 3,
+            skipped: 0,
+            failed: 1,
+            failures: [
+              {
+                shard: 0,
+                index: 'sample-01-rollup',
+                node: 'VFTFJxpHSdaoiGxJFLSExQ',
+                reason: {
+                  type: 'illegal_argument_exception',
+                  reason:
+                    'Field [kubernetes.container.memory.available.bytes] of type [aggregate_metric_double] is not supported for aggregation [percentiles]',
+                },
+              },
+            ],
+          },
+        }as unknown as estypes.SearchResponse<any>}
+        onClose={jest.fn()}
+      />
+    );
+
+    expect(component).toMatchSnapshot();
+  });
+
+  test('should render time out', () => {
+    const component = shallow(
+      <IncompleteResultsModal
+        warning={{} as unknown as SearchResponseIncompleteWarning}
+        request={{}}
+        response={{
+          timed_out: true,
+          _shards: {
+            total: 4,
+            successful: 4,
+            skipped: 0,
+            failed: 0,
+          },
+        } as unknown as estypes.SearchResponse<any>}
+        onClose={jest.fn()}
+      />
+    );
+
+    expect(component).toMatchSnapshot();
+  });
+});

src/plugins/data/public/incomplete_results_modal/incomplete_results_modal.tsx

@@ -62,7 +62,7 @@ export function IncompleteResultsModal({ request, response, warning, onClose }:
             </EuiCallOut>
           ) : null}
 
-          {response._shards.failures.length ? (
+          {response._shards.failures?.length ? (
             <ShardFailureTable failures={response._shards.failures ?? []} />
           ) : null}
         </>