update kbn grouping tests and create unit tests for useLatestFindings…

…Grouping hook

src/platform/packages/shared/kbn-grouping/src/components/grouping.mock.tsx

@@ -130,6 +130,9 @@ export const mockGroupingProps = {
     unitsCountWithoutNull: {
       value: 14,
     },
+    nullGroupItems: {
+      doc_count: 1,
+    },
   },
   groupingId: 'test-grouping-id',
   isLoading: false,

src/platform/packages/shared/kbn-grouping/src/components/grouping.test.tsx

@@ -223,5 +223,32 @@ describe('Grouping', () => {
       expect(customGroupsUnit).toHaveBeenCalledWith(3, testProps.selectedGroup, true);
       expect(screen.getByTestId('group-count').textContent).toBe('3 custom units');
     });
+
+    it('calls custom groupsUnit callback with hasNullGroup = false', () => {
+      const customGroupsUnit = jest.fn(
+        (n, parentSelectedGroup, hasNullGroup) => `${n} custom units`
+      );
+
+      const customProps = {
+        ...testProps,
+        groupsUnit: customGroupsUnit,
+        data: {
+          ...testProps.data,
+          nullGroupItems: {
+            ...testProps.data.nullGroupItems,
+            doc_count: 0,
+          },
+        },
+      };
+
+      render(
+        <I18nProvider>
+          <Grouping {...customProps} />
+        </I18nProvider>
+      );
+
+      expect(customGroupsUnit).toHaveBeenCalledWith(3, testProps.selectedGroup, false);
+      expect(screen.getByTestId('group-count').textContent).toBe('3 custom units');
+    });
   });
 });

x-pack/solutions/security/plugins/cloud_security_posture/public/pages/configurations/latest_findings/use_latest_findings_grouping.test.tsx

@@ -0,0 +1,122 @@
+/*
+ * 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; you may not use this file except in compliance with the Elastic License
+ * 2.0.
+ */
+import React from 'react';
+import { renderHook } from '@testing-library/react';
+import { useLatestFindingsGrouping } from './use_latest_findings_grouping';
+import { useCloudSecurityGrouping } from '../../../components/cloud_security_grouping';
+import { useDataViewContext } from '../../../common/contexts/data_view_context';
+import { useGetCspBenchmarkRulesStatesApi } from '@kbn/cloud-security-posture/src/hooks/use_get_benchmark_rules_state_api';
+import { getGroupingQuery } from '@kbn/grouping';
+import { useGroupedFindings } from './use_grouped_findings';
+
+jest.mock('../../../components/cloud_security_grouping');
+jest.mock('../../../common/contexts/data_view_context');
+jest.mock('@kbn/cloud-security-posture/src/hooks/use_get_benchmark_rules_state_api');
+jest.mock('@kbn/grouping', () => ({
+  getGroupingQuery: jest.fn().mockImplementation((params) => {
+    return {
+      query: { bool: {} },
+    };
+  }),
+  parseGroupingQuery: jest.fn().mockReturnValue({}),
+}));
+jest.mock('./use_grouped_findings');
+
+describe('useLatestFindingsGrouping', () => {
+  const mockGroupPanelRenderer = (
+    selectedGroup: string,
+    fieldBucket: any,
+    nullGroupMessage?: string,
+    isLoading?: boolean
+  ) => <div>Mock Group Panel Renderer</div>;
+  const mockGetGroupStats = jest.fn();
+
+  beforeEach(() => {
+    (useCloudSecurityGrouping as jest.Mock).mockReturnValue({
+      grouping: { selectedGroups: ['cloud.account.id'] },
+    });
+    (useDataViewContext as jest.Mock).mockReturnValue({ dataView: {} });
+    (useGetCspBenchmarkRulesStatesApi as jest.Mock).mockReturnValue({ data: {} });
+    (useGroupedFindings as jest.Mock).mockReturnValue({
+      data: {},
+      isFetching: false,
+    });
+  });
+
+  it('calls getGroupingQuery with correct rootAggregations', () => {
+    renderHook(() =>
+      useLatestFindingsGrouping({
+        groupPanelRenderer: mockGroupPanelRenderer,
+        getGroupStats: mockGetGroupStats,
+        groupingLevel: 0,
+        groupFilters: [],
+        selectedGroup: 'cloud.account.id',
+      })
+    );
+
+    expect(getGroupingQuery).toHaveBeenCalledWith(
+      expect.objectContaining({
+        rootAggregations: [
+          {
+            failedFindings: {
+              filter: {
+                term: {
+                  'result.evaluation': { value: 'failed' },
+                },
+              },
+            },
+            passedFindings: {
+              filter: {
+                term: {
+                  'result.evaluation': { value: 'passed' },
+                },
+              },
+            },
+            nullGroupItems: {
+              missing: { field: 'cloud.account.id' },
+            },
+          },
+        ],
+      })
+    );
+  });
+
+  it('calls getGroupingQuery without nullGroupItems when selectedGroup is "none"', () => {
+    renderHook(() =>
+      useLatestFindingsGrouping({
+        groupPanelRenderer: mockGroupPanelRenderer,
+        getGroupStats: mockGetGroupStats,
+        groupingLevel: 0,
+        groupFilters: [],
+        selectedGroup: 'none',
+      })
+    );
+
+    expect(getGroupingQuery).toHaveBeenCalledWith(
+      expect.objectContaining({
+        rootAggregations: [
+          {
+            failedFindings: {
+              filter: {
+                term: {
+                  'result.evaluation': { value: 'failed' },
+                },
+              },
+            },
+            passedFindings: {
+              filter: {
+                term: {
+                  'result.evaluation': { value: 'passed' },
+                },
+              },
+            },
+          },
+        ],
+      })
+    );
+  });
+});