diff --git a/src/plugins/data/public/search/aggs/test_helpers/mock_data_services.ts b/src/plugins/data/public/search/aggs/test_helpers/mock_data_services.ts
index d1d591771743c..e807e084c683a 100644
--- a/src/plugins/data/public/search/aggs/test_helpers/mock_data_services.ts
+++ b/src/plugins/data/public/search/aggs/test_helpers/mock_data_services.ts
@@ -18,8 +18,8 @@
  */
 
 // eslint-disable-next-line @kbn/eslint/no-restricted-paths
-import { coreMock } from '../../../../../../../src/core/public/mocks';
-import { dataPluginMock } from '../../../../public/mocks';
+import { coreMock } from '../../../../../../core/public/mocks';
+import { dataPluginMock } from '../../../mocks';
 import {
   setFieldFormats,
   setIndexPatterns,
@@ -29,7 +29,7 @@ import {
   setQueryService,
   setSearchService,
   setUiSettings,
-} from '../../../../public/services';
+} from '../../../services';
 
 /**
  * Testing helper which calls all of the service setters used in the
@@ -49,4 +49,9 @@ export function mockDataServices() {
   setQueryService(data.query);
   setSearchService(data.search);
   setUiSettings(core.uiSettings);
+
+  return {
+    core,
+    data,
+  };
 }
diff --git a/src/plugins/data/public/search/legacy/default_search_strategy.test.ts b/src/plugins/data/public/search/legacy/default_search_strategy.test.ts
index 4eaff0b500281..835b02b3cd5c7 100644
--- a/src/plugins/data/public/search/legacy/default_search_strategy.test.ts
+++ b/src/plugins/data/public/search/legacy/default_search_strategy.test.ts
@@ -38,12 +38,6 @@ const searchMockResponse: any = Promise.resolve([]);
 searchMockResponse.abort = jest.fn();
 const searchMock = jest.fn().mockReturnValue(searchMockResponse);
 
-const newSearchMockResponse: any = Promise.resolve([]);
-newSearchMockResponse.abort = jest.fn();
-const newSearchMock = jest.fn().mockReturnValue({
-  toPromise: () => searchMockResponse,
-});
-
 describe('defaultSearchStrategy', function() {
   describe('search', function() {
     let searchArgs: MockedKeys<Omit<SearchStrategySearchParams, 'config'>>;
@@ -58,7 +52,6 @@ describe('defaultSearchStrategy', function() {
 
       const searchService = searchStartMock;
       searchService.aggs.calculateAutoTimeExpression = jest.fn().mockReturnValue('1d');
-      searchService.search = newSearchMock;
       searchService.__LEGACY.esClient.search = searchMock;
       searchService.__LEGACY.esClient.msearch = msearchMock;
 
@@ -112,18 +105,5 @@ describe('defaultSearchStrategy', function() {
       search({ ...searchArgs, config }).abort();
       expect(msearchMockResponse.abort).toHaveBeenCalled();
     });
-
-    test('should call new search service', () => {
-      const config = getConfigStub();
-      search({ ...searchArgs, config });
-      expect(newSearchMock).toHaveBeenCalledTimes(1);
-    });
-
-    test('should properly abort with new search service', async () => {
-      const abortSpy = jest.spyOn(AbortController.prototype, 'abort');
-      const config = getConfigStub({});
-      search({ ...searchArgs, config }).abort();
-      expect(abortSpy).toHaveBeenCalled();
-    });
   });
 });
diff --git a/src/plugins/data/public/search/search_source/search_source.test.ts b/src/plugins/data/public/search/search_source/search_source.test.ts
index 6bad093d31402..fbbc2bbce2b42 100644
--- a/src/plugins/data/public/search/search_source/search_source.test.ts
+++ b/src/plugins/data/public/search/search_source/search_source.test.ts
@@ -20,8 +20,28 @@
 import { SearchSource } from './search_source';
 import { IndexPattern, SortDirection } from '../..';
 import { mockDataServices } from '../aggs/test_helpers';
+import { setSearchService } from '../../services';
+import { searchStartMock } from '../mocks';
+import { fetchSoon } from '../legacy';
+import { CoreStart } from 'kibana/public';
 
-jest.mock('../fetch', () => ({
+// Setup search service mock
+searchStartMock.search = jest.fn(() => {
+  return {
+    toPromise: () => {
+      return new Promise(resolve => {
+        setTimeout(() => {
+          resolve({
+            rawResponse: '',
+          });
+        }, 100);
+      });
+    },
+  };
+}) as any;
+setSearchService(searchStartMock);
+
+jest.mock('../legacy', () => ({
   fetchSoon: jest.fn().mockResolvedValue({}),
 }));
 
@@ -44,8 +64,11 @@ const indexPattern2 = ({
 } as unknown) as IndexPattern;
 
 describe('SearchSource', function() {
+  let uiSettingsMock: jest.Mocked<CoreStart['uiSettings']>;
   beforeEach(() => {
-    mockDataServices();
+    const { core } = mockDataServices();
+    uiSettingsMock = core.uiSettings;
+    jest.clearAllMocks();
   });
 
   describe('#setField()', function() {
@@ -151,6 +174,36 @@ describe('SearchSource', function() {
     });
   });
 
+  describe('#legacy fetch()', () => {
+    beforeEach(() => {
+      uiSettingsMock.get.mockImplementation(() => {
+        return true; // batchSearches = true
+      });
+    });
+
+    afterEach(() => {
+      uiSettingsMock.get.mockImplementation(() => {
+        return false; // batchSearches = false
+      });
+    });
+
+    it('should call msearch', async () => {
+      const searchSource = new SearchSource({ index: indexPattern });
+      const options = {};
+      await searchSource.fetch(options);
+      expect(fetchSoon).toBeCalledTimes(1);
+    });
+  });
+
+  describe('#search service fetch()', () => {
+    it('should call msearch', async () => {
+      const searchSource = new SearchSource({ index: indexPattern });
+      const options = {};
+      await searchSource.fetch(options);
+      expect(searchStartMock.search).toBeCalledTimes(1);
+    });
+  });
+
   describe('#serialize', function() {
     it('should reference index patterns', () => {
       const indexPattern123 = { id: '123' } as IndexPattern;