diff --git a/backend/src/federation/validateCommunities.test.ts b/backend/src/federation/validateCommunities.test.ts
new file mode 100644
index 000000000..4ccc05a3b
--- /dev/null
+++ b/backend/src/federation/validateCommunities.test.ts
@@ -0,0 +1,159 @@
+/* eslint-disable @typescript-eslint/no-explicit-any */
+/* eslint-disable @typescript-eslint/explicit-module-boundary-types */
+
+import CONFIG from '@/config'
+import { logger } from '@test/testSetup'
+import { Community as DbCommunity } from '@entity/Community'
+import { testEnvironment, cleanDB } from '@test/helpers'
+import { startValidateCommunities, validateCommunities } from './validateCommunities'
+
+let con: any
+let testEnv: any
+
+beforeAll(async () => {
+  testEnv = await testEnvironment(logger)
+  con = testEnv.con
+  await cleanDB()
+})
+
+afterAll(async () => {
+  // await cleanDB()
+  await con.close()
+})
+
+describe('validate Communities', () => {
+  /*
+  describe('start validation loop', () => {
+    beforeEach(async () => {
+      jest.clearAllMocks()
+      startValidateCommunities(0)
+    })
+
+    it('logs loop started', () => {
+      expect(logger.info).toBeCalledWith(
+        `Federation: startValidateCommunities loop with an interval of 0 ms...`,
+      )
+    })
+  })
+  */
+  describe('start validation logic without loop', () => {
+    beforeEach(async () => {
+      jest.clearAllMocks()
+      await validateCommunities()
+    })
+
+    it('logs zero communities found', () => {
+      expect(logger.debug).toBeCalledWith(`Federation: found 0 dbCommunities`)
+    })
+
+    describe('with one Community of api 1_0', () => {
+      beforeEach(async () => {
+        const variables1 = {
+          publicKey: Buffer.from('11111111111111111111111111111111'),
+          apiVersion: '1_0',
+          endPoint: 'http//localhost:5001/api/',
+          lastAnnouncedAt: new Date(),
+        }
+        await DbCommunity.createQueryBuilder()
+          .insert()
+          .into(DbCommunity)
+          .values(variables1)
+          .orUpdate({
+            conflict_target: ['id', 'publicKey', 'apiVersion'],
+            overwrite: ['end_point', 'last_announced_at'],
+          })
+          .execute()
+
+        jest.clearAllMocks()
+        await validateCommunities()
+      })
+
+      it('logs one community found', () => {
+        expect(logger.debug).toBeCalledWith(`Federation: found 1 dbCommunities`)
+      })
+      it('logs requestGetPublicKey for community api 1_0 ', () => {
+        expect(logger.info).toBeCalledWith(
+          `requestGetPublicKey with endpoint='http//localhost:5001/api/1_0/getPublicKey'...`,
+        )
+      })
+    })
+    describe('with two Communities of api 1_0 and 1_1', () => {
+      beforeEach(async () => {
+        const variables2 = {
+          publicKey: Buffer.from('11111111111111111111111111111111'),
+          apiVersion: '1_1',
+          endPoint: 'http//localhost:5001/api/',
+          lastAnnouncedAt: new Date(),
+        }
+        await DbCommunity.createQueryBuilder()
+          .insert()
+          .into(DbCommunity)
+          .values(variables2)
+          .orUpdate({
+            conflict_target: ['id', 'publicKey', 'apiVersion'],
+            overwrite: ['end_point', 'last_announced_at'],
+          })
+          .execute()
+
+        jest.clearAllMocks()
+        await validateCommunities()
+      })
+      it('logs two communities found', () => {
+        expect(logger.debug).toBeCalledWith(`Federation: found 2 dbCommunities`)
+      })
+      it('logs requestGetPublicKey for community api 1_0 ', () => {
+        expect(logger.info).toBeCalledWith(
+          `requestGetPublicKey with endpoint='http//localhost:5001/api/1_0/getPublicKey'...`,
+        )
+      })
+      it('logs requestGetPublicKey for community api 1_1 ', () => {
+        expect(logger.info).toBeCalledWith(
+          `requestGetPublicKey with endpoint='http//localhost:5001/api/1_1/getPublicKey'...`,
+        )
+      })
+    })
+    describe('with three Communities of api 1_0, 1_1 and 2_0', () => {
+      let dbCom: DbCommunity
+      beforeEach(async () => {
+        const variables3 = {
+          publicKey: Buffer.from('11111111111111111111111111111111'),
+          apiVersion: '2_0',
+          endPoint: 'http//localhost:5001/api/',
+          lastAnnouncedAt: new Date(),
+        }
+        await DbCommunity.createQueryBuilder()
+          .insert()
+          .into(DbCommunity)
+          .values(variables3)
+          .orUpdate({
+            conflict_target: ['id', 'publicKey', 'apiVersion'],
+            overwrite: ['end_point', 'last_announced_at'],
+          })
+          .execute()
+        dbCom = await DbCommunity.findOneOrFail({
+          where: { publicKey: variables3.publicKey, apiVersion: variables3.apiVersion },
+        })
+        jest.clearAllMocks()
+        await validateCommunities()
+      })
+      it('logs three community found', () => {
+        expect(logger.debug).toBeCalledWith(`Federation: found 3 dbCommunities`)
+      })
+      it('logs requestGetPublicKey for community api 1_0 ', () => {
+        expect(logger.info).toBeCalledWith(
+          `requestGetPublicKey with endpoint='http//localhost:5001/api/1_0/getPublicKey'...`,
+        )
+      })
+      it('logs requestGetPublicKey for community api 1_1 ', () => {
+        expect(logger.info).toBeCalledWith(
+          `requestGetPublicKey with endpoint='http//localhost:5001/api/1_1/getPublicKey'...`,
+        )
+      })
+      it('logs unsupported api for community with api 2_0 ', () => {
+        expect(logger.warn).toBeCalledWith(
+          `Federation: dbCom: ${dbCom.id} with unsupported apiVersion=2_0; supported versions=1_0,1_1`,
+        )
+      })
+    })
+  })
+})
diff --git a/backend/src/federation/validateCommunities.ts b/backend/src/federation/validateCommunities.ts
index da76698c5..9a978fbb9 100644
--- a/backend/src/federation/validateCommunities.ts
+++ b/backend/src/federation/validateCommunities.ts
@@ -12,45 +12,49 @@ export async function startValidateCommunities(timerInterval: number): Promise<v
     `Federation: startValidateCommunities loop with an interval of ${timerInterval} ms...`,
   )
   while (true) {
-    const dbCommunities: DbCommunity[] = await DbCommunity.createQueryBuilder()
-      .where({ verifiedAt: IsNull() })
-      .orWhere('verified_at < last_announced_at')
-      .getMany()
-    /*
-    const dbCommunities: DbCommunity[] = await DbCommunity.getRepository().manager.query(
-      'SELECT * FROM `communities` `Community` WHERE (`Community`.`verified_at` IS NULL OR `Community`.`verified_at` < `Community`.`last_announced_at`)',
-    )
-    */
-    logger.debug(`Federation: found ${dbCommunities.length} dbCommunities`)
-    if (dbCommunities) {
-      dbCommunities.forEach(async function (dbCom) {
-        logger.debug(`Federation: dbCom: ${JSON.stringify(dbCom)}`)
-        const apiValueStrings: string[] = Object.values(ApiVersionType)
-        logger.debug(`suppported ApiVersions=`, apiValueStrings)
-        if (apiValueStrings.includes(dbCom.apiVersion)) {
-          logger.debug(
-            `Federation: validate publicKey for dbCom: ${dbCom.id} with apiVersion=${dbCom.apiVersion}`,
-          )
-          const pubKey = await invokeVersionedRequestGetPublicKey(dbCom)
-          logger.debug(`Federation: received publicKey:  ${pubKey}`)
-          if (pubKey && pubKey === dbCom.publicKey.toString('hex')) {
-            logger.debug(`Federation: matching publicKey:  ${pubKey}`)
-            DbCommunity.update({ id: dbCom.id }, { verifiedAt: new Date() })
-            logger.debug(`Federation: updated dbCom:  ${JSON.stringify(dbCom)}`)
-          }
-        } else {
-          logger.debug(
-            `Federation: dbCom: ${dbCom.id} with unsupported apiVersion=${dbCom.apiVersion}; supported versions=${apiValueStrings}`,
-          )
-        }
-      })
-    }
+    validateCommunities()
     logger.debug(`Federation: loop starts sleeping...`)
     await sleep(timerInterval)
     logger.debug(`Federation: loop ends sleeping`)
   }
 }
 
+export async function validateCommunities(): Promise<void> {
+  const dbCommunities: DbCommunity[] = await DbCommunity.createQueryBuilder()
+    .where({ verifiedAt: IsNull() })
+    .orWhere('verified_at < last_announced_at')
+    .getMany()
+  /*
+  const dbCommunities: DbCommunity[] = await DbCommunity.getRepository().manager.query(
+    'SELECT * FROM `communities` `Community` WHERE (`Community`.`verified_at` IS NULL OR `Community`.`verified_at` < `Community`.`last_announced_at`)',
+  )
+  */
+  logger.debug(`Federation: found ${dbCommunities.length} dbCommunities`)
+  if (dbCommunities) {
+    dbCommunities.forEach(async function (dbCom) {
+      logger.debug(`Federation: dbCom: ${JSON.stringify(dbCom)}`)
+      const apiValueStrings: string[] = Object.values(ApiVersionType)
+      logger.debug(`suppported ApiVersions=`, apiValueStrings)
+      if (apiValueStrings.includes(dbCom.apiVersion)) {
+        logger.debug(
+          `Federation: validate publicKey for dbCom: ${dbCom.id} with apiVersion=${dbCom.apiVersion}`,
+        )
+        const pubKey = await invokeVersionedRequestGetPublicKey(dbCom)
+        logger.debug(`Federation: received publicKey:  ${pubKey}`)
+        if (pubKey && pubKey === dbCom.publicKey.toString('hex')) {
+          logger.debug(`Federation: matching publicKey:  ${pubKey}`)
+          DbCommunity.update({ id: dbCom.id }, { verifiedAt: new Date() })
+          logger.debug(`Federation: updated dbCom:  ${JSON.stringify(dbCom)}`)
+        }
+      } else {
+        logger.warn(
+          `Federation: dbCom: ${dbCom.id} with unsupported apiVersion=${dbCom.apiVersion}; supported versions=${apiValueStrings}`,
+        )
+      }
+    })
+  }
+}
+
 function sleep(ms: number) {
   return new Promise((resolve) => setTimeout(resolve, ms))
 }