diff --git a/src/lib/db/transactional.ts b/src/lib/db/transactional.ts
index 561d3783c4..535a8a6206 100644
--- a/src/lib/db/transactional.ts
+++ b/src/lib/db/transactional.ts
@@ -38,3 +38,35 @@ export abstract class Transactor<T> implements Transactional<T> {
         expectTransaction(db);
     }
 }
+
+export type KnexTransaction = Knex.Transaction<any, any[]>;
+
+export type MockTransaction = null;
+
+export type UnleashTransaction = KnexTransaction | MockTransaction;
+
+export type TransactionCreator<S> = <T>(
+    scope: (trx: S) => void | Promise<T>,
+) => Promise<T>;
+
+export const createKnexTransactionStarter = (
+    knex: Knex,
+): TransactionCreator<UnleashTransaction> => {
+    function transaction<T>(
+        scope: (trx: KnexTransaction) => void | Promise<T>,
+    ) {
+        return knex.transaction(scope);
+    }
+    return transaction;
+};
+
+export const createMockTransactionStarter =
+    (): TransactionCreator<UnleashTransaction> => {
+        function transaction<T>(
+            scope: (trx: MockTransaction) => void | Promise<T>,
+        ) {
+            scope(null);
+            return null;
+        }
+        return transaction;
+    };
diff --git a/src/lib/services/group-service.ts b/src/lib/services/group-service.ts
index be76bb0c94..b938d8ca1e 100644
--- a/src/lib/services/group-service.ts
+++ b/src/lib/services/group-service.ts
@@ -15,7 +15,7 @@ import { IEventStore } from '../types/stores/event-store';
 import NameExistsError from '../error/name-exists-error';
 import { IUserStore } from '../types/stores/user-store';
 import { IUser } from '../types/user';
-import { Knex } from 'knex';
+import { TransactionCreator, UnleashTransaction } from 'lib/db/transactional';
 
 export class GroupService {
     private groupStore: IGroupStore;
@@ -26,18 +26,18 @@ export class GroupService {
 
     private logger: Logger;
 
-    private db: Knex;
+    private startTransaction: TransactionCreator<UnleashTransaction>;
 
     constructor(
         stores: Pick<IUnleashStores, 'groupStore' | 'eventStore' | 'userStore'>,
         { getLogger }: Pick<IUnleashConfig, 'getLogger'>,
-        db: Knex,
+        startTransaction: TransactionCreator<UnleashTransaction>,
     ) {
         this.logger = getLogger('service/group-service.js');
         this.groupStore = stores.groupStore;
         this.eventStore = stores.eventStore;
         this.userStore = stores.userStore;
-        this.db = db;
+        this.startTransaction = startTransaction;
     }
 
     async getAll(): Promise<IGroupModel[]> {
@@ -108,7 +108,7 @@ export class GroupService {
 
         await this.validateGroup(group, preData);
 
-        return this.db.transaction(async (tx) => {
+        return this.startTransaction(async (tx) => {
             const newGroup = await this.groupStore
                 .transactional(tx)
                 .update(group);
@@ -232,7 +232,7 @@ export class GroupService {
         createdBy?: string,
     ): Promise<void> {
         if (Array.isArray(externalGroups)) {
-            await this.db.transaction(async (trx) => {
+            await this.startTransaction(async (trx) => {
                 let newGroups = await this.groupStore
                     .transactional(trx)
                     .getNewGroupsForExternalUser(userId, externalGroups);
diff --git a/src/lib/services/index.ts b/src/lib/services/index.ts
index df4ab2ecd7..9f3ef33bc0 100644
--- a/src/lib/services/index.ts
+++ b/src/lib/services/index.ts
@@ -37,12 +37,14 @@ import PatService from './pat-service';
 import { PublicSignupTokenService } from './public-signup-token-service';
 import { LastSeenService } from './client-metrics/last-seen-service';
 import { Knex } from 'knex';
+import { createKnexTransactionStarter } from '../db/transactional';
 export const createServices = (
     stores: IUnleashStores,
     config: IUnleashConfig,
     db: Knex,
 ): IUnleashServices => {
-    const groupService = new GroupService(stores, config, db);
+    let startTransaction = createKnexTransactionStarter(db);
+    const groupService = new GroupService(stores, config, startTransaction);
     const accessService = new AccessService(stores, config, groupService);
     const apiTokenService = new ApiTokenService(stores, config);
     const clientInstanceService = new ClientInstanceService(stores, config);
diff --git a/src/lib/types/stores/transactional.ts b/src/lib/types/stores/transactional.ts
index fc44176d02..81c765d1f1 100644
--- a/src/lib/types/stores/transactional.ts
+++ b/src/lib/types/stores/transactional.ts
@@ -1,5 +1,5 @@
-import { Knex } from 'knex';
+import { UnleashTransaction } from 'lib/db/transactional';
 
 export interface Transactional<T> {
-    transactional(transaction: Knex.Transaction): T;
+    transactional(transaction: UnleashTransaction): T;
 }
diff --git a/src/test/e2e/services/group-service.e2e.test.ts b/src/test/e2e/services/group-service.e2e.test.ts
index 14bfd1ca83..473a31a5af 100644
--- a/src/test/e2e/services/group-service.e2e.test.ts
+++ b/src/test/e2e/services/group-service.e2e.test.ts
@@ -3,6 +3,7 @@ import getLogger from '../../fixtures/no-logger';
 import { createTestConfig } from '../../config/test-config';
 import { GroupService } from '../../../lib/services/group-service';
 import GroupStore from '../../../lib/db/group-store';
+import { createKnexTransactionStarter } from '../../../lib/db/transactional';
 
 let stores;
 let db: ITestDb;
@@ -21,7 +22,8 @@ beforeAll(async () => {
     const config = createTestConfig({
         getLogger,
     });
-    groupService = new GroupService(stores, config, db.db);
+    let startTransaction = createKnexTransactionStarter(db.db);
+    groupService = new GroupService(stores, config, startTransaction);
     groupStore = stores.groupStore;
 
     await stores.groupStore.create({
diff --git a/src/test/fixtures/fake-group-store.ts b/src/test/fixtures/fake-group-store.ts
index 5d307fa126..7c02d23419 100644
--- a/src/test/fixtures/fake-group-store.ts
+++ b/src/test/fixtures/fake-group-store.ts
@@ -7,11 +7,15 @@ import Group, {
     IGroupUser,
     IGroupUserModel,
 } from '../../lib/types/group';
-import { Knex } from 'knex';
+import { UnleashTransaction } from 'lib/db/transactional';
 /* eslint-disable @typescript-eslint/no-unused-vars */
 export default class FakeGroupStore implements IGroupStore {
     data: IGroup[];
 
+    constructor() {
+        this.data = [];
+    }
+
     async getAll(): Promise<IGroup[]> {
         return Promise.resolve(this.data);
     }
@@ -56,7 +60,7 @@ export default class FakeGroupStore implements IGroupStore {
     }
 
     deleteUsersFromGroup(deletableUsers: IGroupUser[]): Promise<void> {
-        throw new Error('Method not implemented.');
+        return Promise.resolve();
     }
 
     update(group: IGroupModel): Promise<IGroup> {
@@ -89,7 +93,13 @@ export default class FakeGroupStore implements IGroupStore {
         userId: number,
         externalGroups: string[],
     ): Promise<IGroup[]> {
-        throw new Error('Method not implemented.');
+        const mockGroups = externalGroups.map((externalGroup, index) => {
+            return {
+                id: index,
+                name: externalGroup,
+            };
+        });
+        return Promise.resolve(mockGroups);
     }
 
     addUserToGroups(
@@ -97,21 +107,34 @@ export default class FakeGroupStore implements IGroupStore {
         groupIds: number[],
         createdBy?: string,
     ): Promise<void> {
-        throw new Error('Method not implemented.');
+        groupIds.forEach((groupId) => {
+            this.data.push({
+                id: groupId,
+                name: `TestGroup-${groupId}`,
+            });
+        });
+        return Promise.resolve();
     }
 
     getOldGroupsForExternalUser(
         userId: number,
         externalGroups: string[],
     ): Promise<IGroupUser[]> {
-        throw new Error('Method not implemented.');
+        const mockGroups = externalGroups.map((externalGroup, index) => {
+            return {
+                groupId: index,
+                userId: index,
+                joinedAt: new Date(),
+            };
+        });
+        return Promise.resolve(mockGroups);
     }
 
     getGroupsForUser(userId: number): Promise<Group[]> {
         throw new Error('Method not implemented.');
     }
 
-    transactional(transaction: Knex.Transaction<any, any[]>): IGroupStore {
-        throw new Error('Method not implemented.');
+    transactional(transaction: UnleashTransaction): IGroupStore {
+        return this;
     }
 }
diff --git a/src/test/transactional.test.ts b/src/test/transactional.test.ts
index 9bad637e8a..0f22ea1e52 100644
--- a/src/test/transactional.test.ts
+++ b/src/test/transactional.test.ts
@@ -1,11 +1,20 @@
+import { createMockTransactionStarter } from '../lib/db/transactional';
+import { IUnleashConfig } from '../lib/server-impl';
+import { GroupService } from '../lib/services/group-service';
 import dbInit, { ITestDb } from './/e2e/helpers/database-init';
-import getLogger from './fixtures/no-logger';
+import { createTestConfig } from './config/test-config';
+import FakeGroupStore from './fixtures/fake-group-store';
+import noLoggerProvider from './fixtures/no-logger';
 
 let stores;
 let db: ITestDb;
+let config: IUnleashConfig;
 
 beforeAll(async () => {
-    db = await dbInit('transactional_serial', getLogger);
+    db = await dbInit('transactional_serial', noLoggerProvider);
+    config = createTestConfig({
+        getLogger: noLoggerProvider,
+    });
     stores = db.stores;
 });
 
@@ -141,3 +150,24 @@ test('should fail entire transaction if encountering an error', async () => {
     const toggles = await stores.featureToggleStore.getAll();
     expect(toggles.length).toBe(0);
 });
+
+test('should allow transactions be swapped for a different implementation', async () => {
+    const mockStores = {
+        groupStore: new FakeGroupStore(),
+        eventStore: null,
+        userStore: null,
+    };
+
+    expect((await mockStores.groupStore.getAll()).length).toBe(0);
+
+    const groupService = new GroupService(
+        mockStores,
+        config,
+        createMockTransactionStarter(),
+    );
+    const externalGroups = ['group-one', 'group-two'];
+
+    await groupService.syncExternalGroups(7, externalGroups, 'David Fincher');
+
+    expect((await mockStores.groupStore.getAll()).length).toBe(2);
+});