diff --git a/test/unit/adapters/REST/endpoints/app-action-call.test.ts b/test/unit/adapters/REST/endpoints/app-action-call.test.ts
index 57449b2651..9dc693a4e8 100644
--- a/test/unit/adapters/REST/endpoints/app-action-call.test.ts
+++ b/test/unit/adapters/REST/endpoints/app-action-call.test.ts
@@ -1,7 +1,6 @@
-import { vi, expect, describe, it } from 'vitest'
+import { expect, describe, it } from 'vitest'
 import { cloneMock } from '../../../mocks/entities'
 import setupRestAdapter from '../helpers/setupRestAdapter'
-import contentfulSdkCore from 'contentful-sdk-core'
 
 import {
   CreateAppActionCallProps,
@@ -9,14 +8,6 @@ import {
 } from '../../../../../lib/entities/app-action-call'
 import { MakeRequest, MakeRequestOptions } from '../../../../../lib/export-types'
 
-vi.mock('contentful-sdk-core', async (importOriginal) => {
-  const orig = await importOriginal<typeof contentfulSdkCore>()
-  return {
-    ...orig,
-    createHttpClient: vi.fn(),
-  }
-})
-
 function setup(promise, mockName, params = {}) {
   const entityMock = cloneMock(mockName)
   return {
@@ -25,7 +16,7 @@ function setup(promise, mockName, params = {}) {
   }
 }
 
-describe('Rest App Action Call', { concurrent: 3 }, () => {
+describe('Rest App Action Call', { concurrent: true }, () => {
   it('should create a new App Action Call', async () => {
     const responseMock = cloneMock('appActionCallResponse')
 
diff --git a/test/unit/adapters/REST/endpoints/asset-test.js b/test/unit/adapters/REST/endpoints/asset.test.ts
similarity index 62%
rename from test/unit/adapters/REST/endpoints/asset-test.js
rename to test/unit/adapters/REST/endpoints/asset.test.ts
index 66b2739c46..f9622edeb6 100644
--- a/test/unit/adapters/REST/endpoints/asset-test.js
+++ b/test/unit/adapters/REST/endpoints/asset.test.ts
@@ -1,8 +1,8 @@
-import { describe, test } from 'mocha'
+import { vi, expect, describe, test } from 'vitest'
 import { cloneMock, assetWithFilesMock } from '../../../mocks/entities'
 import { wrapAsset } from '../../../../../lib/entities/asset'
-import { expect } from 'chai'
 import setupRestAdapter from '../helpers/setupRestAdapter'
+import contentfulSdkCore from 'contentful-sdk-core'
 
 function setup(promise, params = {}) {
   return {
@@ -11,6 +11,14 @@ function setup(promise, params = {}) {
   }
 }
 
+vi.mock('contentful-sdk-core', async (importOriginal) => {
+  const orig = await importOriginal<typeof contentfulSdkCore>()
+  return {
+    ...orig,
+    createHttpClient: vi.fn(),
+  }
+})
+
 describe('Rest Asset', async () => {
   test('Asset processing for multiple locales succeeds', async () => {
     const responseMock = cloneMock('asset')
@@ -42,28 +50,28 @@ describe('Rest Asset', async () => {
     entityMock.sys.version = 2
     const entity = wrapAsset((...args) => adapterMock.makeRequest(...args), entityMock)
     return entity.processForAllLocales().then(() => {
-      expect(httpMock.put.args[0][0]).equals(
-        '/spaces/space-id/environments/environment-id/assets/id/files/en-US/process',
+      expect(httpMock.put.mock.calls[0][0]).equals(
+        '/spaces/mock-space-id/environments/mock-environment-id/assets/id/files/en-US/process',
         'en-US locale is sent'
       )
-      expect(httpMock.put.args[1][0]).equals(
-        '/spaces/space-id/environments/environment-id/assets/id/files/de-DE/process',
+      expect(httpMock.put.mock.calls[1][0]).equals(
+        '/spaces/mock-space-id/environments/mock-environment-id/assets/id/files/de-DE/process',
         'de-DE locale is sent'
       )
-      expect(httpMock.put.args[0][2].headers['X-Contentful-Version']).equals(
+      expect(httpMock.put.mock.calls[0][2].headers['X-Contentful-Version']).equals(
         2,
         'version header is sent for first locale'
       )
-      expect(httpMock.put.args[1][2].headers['X-Contentful-Version']).equals(
+      expect(httpMock.put.mock.calls[1][2].headers['X-Contentful-Version']).equals(
         2,
         'version header is sent for second locale'
       )
-      expect(httpMock.get.args[0][0]).equals(
-        '/spaces/space-id/environments/environment-id/assets/id',
+      expect(httpMock.get.mock.calls[0][0]).equals(
+        '/spaces/mock-space-id/environments/mock-environment-id/assets/id',
         'asset was checked after processing for first locale'
       )
-      expect(httpMock.get.args[1][0]).equals(
-        '/spaces/space-id/environments/environment-id/assets/id',
+      expect(httpMock.get.mock.calls[1][0]).equals(
+        '/spaces/mock-space-id/environments/mock-environment-id/assets/id',
         'asset was checked after processing for second locale'
       )
     })
@@ -83,26 +91,22 @@ describe('Rest Asset', async () => {
     entityMock.sys.version = 2
     const entity = wrapAsset((...args) => adapterMock.makeRequest(...args), entityMock)
     return entity.processForLocale('en-US').then(() => {
-      expect(httpMock.put.args[0][0]).equals(
-        '/spaces/space-id/environments/environment-id/assets/id/files/en-US/process',
+      expect(httpMock.put.mock.calls[0][0]).equals(
+        '/spaces/mock-space-id/environments/mock-environment-id/assets/id/files/en-US/process',
         'correct locale is sent'
       )
-      expect(httpMock.put.args[0][2].headers['X-Contentful-Version']).equals(
+      expect(httpMock.put.mock.calls[0][2].headers['X-Contentful-Version']).equals(
         2,
         'version header is sent'
       )
-      expect(httpMock.get.args[0][0]).equals(
-        '/spaces/space-id/environments/environment-id/assets/id',
+      expect(httpMock.get.mock.calls[0][0]).equals(
+        '/spaces/mock-space-id/environments/mock-environment-id/assets/id',
         'asset was checked after processing'
       )
     })
   })
 
-  /*
-    - Test is failing
-    - it also causes a memory leak in watch mode
-   */
-  test.skip('Asset processing for one locale fails due to timeout', async () => {
+  test('Asset processing for one locale fails due to timeout', { timeout: 35_000 }, async () => {
     const responseMock = cloneMock('asset')
     responseMock.fields = {
       file: { 'en-US': { fileName: 'filename.jpg' } }, // url property never sent in response
@@ -113,7 +117,7 @@ describe('Rest Asset', async () => {
     try {
       await entity.processForLocale('en-US')
     } catch (error) {
-      expect(httpMock.get.callCount > 1, 'asset is checked multiple times').to.be.ok
+      expect(httpMock.get.mock.calls.length, 'asset is checked multiple times').toBeGreaterThan(1)
       expect(error.name).equals('AssetProcessingTimeout', 'timeout is thrown')
     }
   })
@@ -148,61 +152,65 @@ describe('Rest Asset', async () => {
     entityMock.sys.version = 2
     const entity = wrapAsset((...args) => adapterMock.makeRequest(...args), entityMock)
     return entity.processForAllLocales().then(() => {
-      expect(httpMock.put.args[0][0]).equals(
-        '/spaces/space-id/environments/environment-id/assets/id/files/en-US/process',
+      expect(httpMock.put.mock.calls[0][0]).equals(
+        '/spaces/mock-space-id/environments/mock-environment-id/assets/id/files/en-US/process',
         'en-US locale is sent'
       )
-      expect(httpMock.put.args[1][0]).equals(
-        '/spaces/space-id/environments/environment-id/assets/id/files/de-DE/process',
+      expect(httpMock.put.mock.calls[1][0]).equals(
+        '/spaces/mock-space-id/environments/mock-environment-id/assets/id/files/de-DE/process',
         'de-DE locale is sent'
       )
-      expect(httpMock.put.args[0][2].headers['X-Contentful-Version']).equals(
+      expect(httpMock.put.mock.calls[0][2].headers['X-Contentful-Version']).equals(
         2,
         'version header is sent for first locale'
       )
-      expect(httpMock.put.args[1][2].headers['X-Contentful-Version']).equals(
+      expect(httpMock.put.mock.calls[1][2].headers['X-Contentful-Version']).equals(
         2,
         'version header is sent for second locale'
       )
-      expect(httpMock.get.args[0][0]).equals(
-        '/spaces/space-id/environments/environment-id/assets/id',
+      expect(httpMock.get.mock.calls[0][0]).equals(
+        '/spaces/mock-space-id/environments/mock-environment-id/assets/id',
         'asset was checked after processing for first locale'
       )
-      expect(httpMock.get.args[1][0]).equals(
-        '/spaces/space-id/environments/environment-id/assets/id',
+      expect(httpMock.get.mock.calls[1][0]).equals(
+        '/spaces/mock-space-id/environments/mock-environment-id/assets/id',
         'asset was checked after processing for second locale'
       )
     })
   })
 
-  test('Asset processing for multiple locales fails due to timeout', async () => {
-    const responseMock = cloneMock('asset')
-    responseMock.fields = {
-      file: {
-        'en-US': { fileName: 'filename.jpg' }, // url property never sent
-        'de-DE': { fileName: 'filename.jpg' }, // url property never sent
-      },
-    }
-    const { httpMock, adapterMock, entityMock } = setup(Promise.resolve({ data: responseMock }))
-    entityMock.fields = {
-      file: {
-        'en-US': {
-          fileName: 'filename.jpg',
-          upload: 'http://server/filename.jpg',
+  test(
+    'Asset processing for multiple locales fails due to timeout',
+    { timeout: 35_000 },
+    async () => {
+      const responseMock = cloneMock('asset')
+      responseMock.fields = {
+        file: {
+          'en-US': { fileName: 'filename.jpg' }, // url property never sent
+          'de-DE': { fileName: 'filename.jpg' }, // url property never sent
         },
-        'de-DE': {
-          fileName: 'filename.jpg',
-          upload: 'http://server/filename.jpg',
+      }
+      const { httpMock, adapterMock, entityMock } = setup(Promise.resolve({ data: responseMock }))
+      entityMock.fields = {
+        file: {
+          'en-US': {
+            fileName: 'filename.jpg',
+            upload: 'http://server/filename.jpg',
+          },
+          'de-DE': {
+            fileName: 'filename.jpg',
+            upload: 'http://server/filename.jpg',
+          },
         },
-      },
+      }
+      entityMock.sys.version = 2
+      const entity = wrapAsset((...args) => adapterMock.makeRequest(...args), entityMock)
+      return entity.processForAllLocales().catch((error) => {
+        expect(httpMock.get.mock.calls.length, 'asset is checked multiple times').toBeGreaterThan(1)
+        expect(error.name).equals('AssetProcessingTimeout', 'timeout is thrown')
+      })
     }
-    entityMock.sys.version = 2
-    const entity = wrapAsset((...args) => adapterMock.makeRequest(...args), entityMock)
-    return entity.processForAllLocales().catch((error) => {
-      expect(httpMock.get.callCount > 1, 'asset is checked multiple times').to.be.ok
-      expect(error.name).equals('AssetProcessingTimeout', 'timeout is thrown')
-    })
-  })
+  )
 
   test('Asset update with tags works', async () => {
     const { adapterMock, httpMock } = setup()
@@ -215,8 +223,11 @@ describe('Rest Asset', async () => {
     }
     return entity.update().then((response) => {
       expect(response.toPlainObject, 'response is wrapped').to.be.ok
-      expect(httpMock.put.args[0][1].metadata.tags[0].name).equals('newname', 'metadata is sent')
-      expect(httpMock.put.args[0][2].headers['X-Contentful-Version']).equals(
+      expect(httpMock.put.mock.calls[0][1].metadata.tags[0].name).equals(
+        'newname',
+        'metadata is sent'
+      )
+      expect(httpMock.put.mock.calls[0][2].headers['X-Contentful-Version']).equals(
         2,
         'version header is sent'
       )
@@ -231,7 +242,7 @@ describe('Rest Asset', async () => {
   test('API call createAssetFromFiles', async () => {
     const { httpMock, adapterMock } = setup(Promise.resolve({}))
 
-    httpMock.post.onFirstCall().returns(
+    httpMock.post.mockReturnValueOnce(
       Promise.resolve({
         data: {
           sys: {
@@ -241,7 +252,7 @@ describe('Rest Asset', async () => {
       })
     )
 
-    httpMock.post.onSecondCall().returns(
+    httpMock.post.mockReturnValueOnce(
       Promise.resolve({
         data: {
           sys: {
@@ -251,7 +262,7 @@ describe('Rest Asset', async () => {
       })
     )
 
-    httpMock.post.onThirdCall().returns(
+    httpMock.post.mockReturnValueOnce(
       Promise.resolve({
         data: assetWithFilesMock,
       })
@@ -280,11 +291,11 @@ describe('Rest Asset', async () => {
         },
       })
       .then(() => {
-        expect(httpMock.post.args[0][1]).equals(
+        expect(httpMock.post.mock.calls[0][1]).equals(
           '<svg xmlns="http://www.w3.org/2000/svg"><path fill="red" d="M50 50h150v50H50z"/></svg>',
           'uploads file #1 to upload endpoint'
         )
-        expect(httpMock.post.args[1][1]).equals(
+        expect(httpMock.post.mock.calls[1][1]).equals(
           '<svg xmlns="http://www.w3.org/2000/svg"><path fill="blue" d="M50 50h150v50H50z"/></svg>',
           'uploads file #2 to upload endpoint'
         )
diff --git a/test/unit/adapters/REST/endpoints/concept-scheme-test.ts b/test/unit/adapters/REST/endpoints/concept-scheme.test.ts
similarity index 75%
rename from test/unit/adapters/REST/endpoints/concept-scheme-test.ts
rename to test/unit/adapters/REST/endpoints/concept-scheme.test.ts
index dc10aa06a2..985f350f70 100644
--- a/test/unit/adapters/REST/endpoints/concept-scheme-test.ts
+++ b/test/unit/adapters/REST/endpoints/concept-scheme.test.ts
@@ -1,6 +1,6 @@
-import { describe, test } from 'mocha'
+import { expect, describe, test } from 'vitest'
+
 import { cloneMock } from '../../../mocks/entities'
-import { expect } from 'chai'
 import setupRestAdapter from '../helpers/setupRestAdapter'
 
 function setup<T>(promise: Promise<T>, params = {}, type = 'conceptScheme') {
@@ -13,12 +13,13 @@ function setup<T>(promise: Promise<T>, params = {}, type = 'conceptScheme') {
 describe('ConceptScheme', () => {
   test('get', async () => {
     const { httpMock, adapterMock, entityMock } = setup(Promise.resolve({}))
-    httpMock.get.returns(Promise.resolve({ data: entityMock }))
+    httpMock.get.mockReturnValue(Promise.resolve({ data: entityMock }))
 
     return adapterMock
       .makeRequest({
         entityType: 'ConceptScheme',
         action: 'get',
+        userAgent: 'mocked',
         params: {
           organizationId: 'organization-id',
           conceptSchemeId: 'concept-scheme-id',
@@ -26,7 +27,7 @@ describe('ConceptScheme', () => {
       })
       .then((r) => {
         expect(r).to.eql(entityMock)
-        expect(httpMock.get.args[0][0]).to.eql(
+        expect(httpMock.get.mock.calls[0][0]).to.eql(
           '/organizations/organization-id/taxonomy/concept-schemes/concept-scheme-id'
         )
       })
@@ -34,30 +35,32 @@ describe('ConceptScheme', () => {
 
   test('getTotal', async () => {
     const { httpMock, adapterMock } = setup(Promise.resolve({}))
-    httpMock.get.returns(Promise.resolve({ data: { total: 1 } }))
+    httpMock.get.mockReturnValue(Promise.resolve({ data: { total: 1 } }))
 
     return adapterMock
       .makeRequest({
         entityType: 'ConceptScheme',
         action: 'getTotal',
+        userAgent: 'mocked',
         params: {
           organizationId: 'organization-id',
         },
       })
       .then(() => {
-        expect(httpMock.get.args[0][0]).to.eql(
+        expect(httpMock.get.mock.calls[0][0]).to.eql(
           '/organizations/organization-id/taxonomy/concept-schemes/total'
         )
       })
   })
   test('create', async () => {
     const { httpMock, adapterMock, entityMock } = setup(Promise.resolve({}))
-    httpMock.post.returns(Promise.resolve({ data: entityMock }))
+    httpMock.post.mockReturnValue(Promise.resolve({ data: entityMock }))
 
     return adapterMock
       .makeRequest({
         entityType: 'ConceptScheme',
         action: 'create',
+        userAgent: 'mocked',
         params: {
           organizationId: 'organization-id',
         },
@@ -65,7 +68,7 @@ describe('ConceptScheme', () => {
       })
       .then((r) => {
         expect(r).to.eql(entityMock)
-        expect(httpMock.post.args[0][0]).to.eql(
+        expect(httpMock.post.mock.calls[0][0]).to.eql(
           '/organizations/organization-id/taxonomy/concept-schemes'
         )
       })
@@ -73,19 +76,20 @@ describe('ConceptScheme', () => {
 
   test('update', async () => {
     const { httpMock, adapterMock, entityMock } = setup(Promise.resolve({}))
-    httpMock.patch.returns(Promise.resolve({ data: entityMock }))
+    httpMock.patch.mockReturnValue(Promise.resolve({ data: entityMock }))
 
     return adapterMock
       .makeRequest({
         entityType: 'ConceptScheme',
         action: 'update',
+        userAgent: 'mocked',
         params: {
           organizationId: 'organization-id',
           conceptSchemeId: 'concept-scheme-id',
         },
       })
       .then(() => {
-        expect(httpMock.patch.args[0][0]).to.eql(
+        expect(httpMock.patch.mock.calls[0][0]).to.eql(
           '/organizations/organization-id/taxonomy/concept-schemes/concept-scheme-id'
         )
       })
@@ -93,12 +97,13 @@ describe('ConceptScheme', () => {
 
   test('delete', async () => {
     const { httpMock, adapterMock } = setup(Promise.resolve({}))
-    httpMock.delete.returns(Promise.resolve({ data: {} }))
+    httpMock.delete.mockReturnValue(Promise.resolve({ data: {} }))
 
     return adapterMock
       .makeRequest({
         entityType: 'ConceptScheme',
         action: 'delete',
+        userAgent: 'mocked',
         params: {
           organizationId: 'organization-id',
           conceptSchemeId: 'concept-scheme-id',
@@ -106,10 +111,10 @@ describe('ConceptScheme', () => {
         },
       })
       .then(() => {
-        expect(httpMock.delete.args[0][0]).to.eql(
+        expect(httpMock.delete.mock.calls[0][0]).to.eql(
           '/organizations/organization-id/taxonomy/concept-schemes/concept-scheme-id'
         )
-        expect(httpMock.delete.args[0][1].headers).to.eql({ 'X-Contentful-Version': 1 })
+        expect(httpMock.delete.mock.calls[0][1].headers).to.eql({ 'X-Contentful-Version': 1 })
       })
   })
 
@@ -135,12 +140,13 @@ describe('ConceptScheme', () => {
     configs.forEach(({ expected, params, name }) => {
       test(name, async () => {
         const { httpMock, adapterMock, entityMock } = setup(Promise.resolve({}))
-        httpMock.get.returns(Promise.resolve({ data: { items: [entityMock] } }))
+        httpMock.get.mockReturnValue(Promise.resolve({ data: { items: [entityMock] } }))
 
         return adapterMock
           .makeRequest({
             entityType: 'ConceptScheme',
             action: 'getMany',
+            userAgent: 'mocked',
             params: {
               organizationId: 'organization-id',
               ...params,
@@ -148,8 +154,8 @@ describe('ConceptScheme', () => {
           })
           .then((r) => {
             expect(r).to.eql({ items: [entityMock] })
-            expect(httpMock.get.args[0][0]).to.eql(expected.url)
-            expect(httpMock.get.args[0][1].params).to.eql(expected.params)
+            expect(httpMock.get.mock.calls[0][0]).to.eql(expected.url)
+            expect(httpMock.get.mock.calls[0][1].params).to.eql(expected.params)
           })
       })
     })
diff --git a/test/unit/adapters/REST/endpoints/concept-test.ts b/test/unit/adapters/REST/endpoints/concept.test.ts
similarity index 75%
rename from test/unit/adapters/REST/endpoints/concept-test.ts
rename to test/unit/adapters/REST/endpoints/concept.test.ts
index 199f7bcd9c..68020117bd 100644
--- a/test/unit/adapters/REST/endpoints/concept-test.ts
+++ b/test/unit/adapters/REST/endpoints/concept.test.ts
@@ -1,6 +1,5 @@
-import { describe, test } from 'mocha'
+import { expect, describe, test } from 'vitest'
 import { cloneMock } from '../../../mocks/entities'
-import { expect } from 'chai'
 import setupRestAdapter from '../helpers/setupRestAdapter'
 
 function setup(promise, params = {}, type = 'concept') {
@@ -14,12 +13,13 @@ describe('Concept', () => {
   test('get', async () => {
     const { httpMock, adapterMock, entityMock } = setup(Promise.resolve({}))
 
-    httpMock.get.returns(Promise.resolve({ data: entityMock }))
+    httpMock.get.mockReturnValue(Promise.resolve({ data: entityMock }))
 
     return adapterMock
       .makeRequest({
         entityType: 'Concept',
         action: 'get',
+        userAgent: 'mocked',
         params: {
           organizationId: 'organization-id',
           conceptId: 'concept-id',
@@ -27,7 +27,7 @@ describe('Concept', () => {
       })
       .then((r) => {
         expect(r).to.eql(entityMock)
-        expect(httpMock.get.args[0][0]).to.eql(
+        expect(httpMock.get.mock.calls[0][0]).to.eql(
           '/organizations/organization-id/taxonomy/concepts/concept-id'
         )
       })
@@ -62,12 +62,13 @@ describe('Concept', () => {
     configs.forEach(({ expected, params, name }) => {
       test(name, async () => {
         const { httpMock, adapterMock, entityMock } = setup(Promise.resolve({}))
-        httpMock.get.returns(Promise.resolve({ data: { items: [entityMock] } }))
+        httpMock.get.mockReturnValue(Promise.resolve({ data: { items: [entityMock] } }))
 
         return adapterMock
           .makeRequest({
             entityType: 'Concept',
             action: 'getMany',
+            userAgent: 'mocked',
             params: {
               organizationId: 'organization-id',
               ...params,
@@ -75,8 +76,8 @@ describe('Concept', () => {
           })
           .then((r) => {
             expect(r).to.eql({ items: [entityMock] })
-            expect(httpMock.get.args[0][0]).to.eql(expected.url)
-            expect(httpMock.get.args[0][1].params).to.eql(expected.params)
+            expect(httpMock.get.mock.calls[0][0]).to.eql(expected.url)
+            expect(httpMock.get.mock.calls[0][1].params).to.eql(expected.params)
           })
       })
     })
@@ -84,18 +85,19 @@ describe('Concept', () => {
   test('getTotal', async () => {
     const { httpMock, adapterMock } = setup(Promise.resolve({}))
 
-    httpMock.get.returns(Promise.resolve({ data: { total: 1 } }))
+    httpMock.get.mockReturnValue(Promise.resolve({ data: { total: 1 } }))
 
     return adapterMock
       .makeRequest({
         entityType: 'Concept',
         action: 'getTotal',
+        userAgent: 'mocked',
         params: {
           organizationId: 'organization-id',
         },
       })
       .then(() => {
-        expect(httpMock.get.args[0][0]).to.eql(
+        expect(httpMock.get.mock.calls[0][0]).to.eql(
           '/organizations/organization-id/taxonomy/concepts/total'
         )
       })
@@ -103,12 +105,13 @@ describe('Concept', () => {
   test('create', async () => {
     const { httpMock, adapterMock, entityMock } = setup(Promise.resolve({}))
 
-    httpMock.post.returns(Promise.resolve({ data: entityMock }))
+    httpMock.post.mockReturnValue(Promise.resolve({ data: entityMock }))
 
     return adapterMock
       .makeRequest({
         entityType: 'Concept',
         action: 'create',
+        userAgent: 'mocked',
         params: {
           organizationId: 'organization-id',
         },
@@ -116,25 +119,28 @@ describe('Concept', () => {
       })
       .then((r) => {
         expect(r).to.eql(entityMock)
-        expect(httpMock.post.args[0][0]).to.eql('/organizations/organization-id/taxonomy/concepts')
+        expect(httpMock.post.mock.calls[0][0]).to.eql(
+          '/organizations/organization-id/taxonomy/concepts'
+        )
       })
   })
   test('update', async () => {
     const { httpMock, adapterMock, entityMock } = setup(Promise.resolve({}))
 
-    httpMock.patch.returns(Promise.resolve({ data: entityMock }))
+    httpMock.patch.mockReturnValue(Promise.resolve({ data: entityMock }))
 
     return adapterMock
       .makeRequest({
         entityType: 'Concept',
         action: 'update',
+        userAgent: 'mocked',
         params: {
           organizationId: 'organization-id',
           conceptId: 'concept-id',
         },
       })
       .then(() => {
-        expect(httpMock.patch.args[0][0]).to.eql(
+        expect(httpMock.patch.mock.calls[0][0]).to.eql(
           '/organizations/organization-id/taxonomy/concepts/concept-id'
         )
       })
@@ -142,19 +148,20 @@ describe('Concept', () => {
   test('delete', async () => {
     const { httpMock, adapterMock } = setup(Promise.resolve({}))
 
-    httpMock.delete.returns(Promise.resolve({ data: {} }))
+    httpMock.delete.mockReturnValue(Promise.resolve({ data: {} }))
 
     return adapterMock
       .makeRequest({
         entityType: 'Concept',
         action: 'delete',
+        userAgent: 'mocked',
         params: {
           organizationId: 'organization-id',
           conceptId: 'concept-id',
         },
       })
       .then(() => {
-        expect(httpMock.delete.args[0][0]).to.eql(
+        expect(httpMock.delete.mock.calls[0][0]).to.eql(
           '/organizations/organization-id/taxonomy/concepts/concept-id'
         )
       })
@@ -162,19 +169,20 @@ describe('Concept', () => {
   test('getDescendants', async () => {
     const { httpMock, adapterMock } = setup(Promise.resolve({}))
 
-    httpMock.get.returns(Promise.resolve({ data: {} }))
+    httpMock.get.mockReturnValue(Promise.resolve({ data: {} }))
 
     return adapterMock
       .makeRequest({
         entityType: 'Concept',
         action: 'getDescendants',
+        userAgent: 'mocked',
         params: {
           organizationId: 'organization-id',
           conceptId: 'concept-id',
         },
       })
       .then(() => {
-        expect(httpMock.get.args[0][0]).to.eql(
+        expect(httpMock.get.mock.calls[0][0]).to.eql(
           '/organizations/organization-id/taxonomy/concepts/concept-id/descendants'
         )
       })
@@ -183,19 +191,20 @@ describe('Concept', () => {
   test('getAncestors', async () => {
     const { httpMock, adapterMock } = setup(Promise.resolve({}))
 
-    httpMock.get.returns(Promise.resolve({ data: {} }))
+    httpMock.get.mockReturnValue(Promise.resolve({ data: {} }))
 
     return adapterMock
       .makeRequest({
         entityType: 'Concept',
         action: 'getAncestors',
+        userAgent: 'mocked',
         params: {
           organizationId: 'organization-id',
           conceptId: 'concept-id',
         },
       })
       .then(() => {
-        expect(httpMock.get.args[0][0]).to.eql(
+        expect(httpMock.get.mock.calls[0][0]).to.eql(
           '/organizations/organization-id/taxonomy/concepts/concept-id/ancestors'
         )
       })
diff --git a/test/unit/adapters/REST/endpoints/entry-test.js b/test/unit/adapters/REST/endpoints/entry.test.ts
similarity index 66%
rename from test/unit/adapters/REST/endpoints/entry-test.js
rename to test/unit/adapters/REST/endpoints/entry.test.ts
index 61372f1564..99503dcb8e 100644
--- a/test/unit/adapters/REST/endpoints/entry-test.js
+++ b/test/unit/adapters/REST/endpoints/entry.test.ts
@@ -1,7 +1,7 @@
-import { describe, test } from 'mocha'
+import { describe, test, expect } from 'vitest'
 import { cloneMock } from '../../../mocks/entities'
 import { wrapEntry } from '../../../../../lib/entities/entry'
-import { expect } from 'chai'
+
 import setupRestAdapter from '../helpers/setupRestAdapter'
 
 function setup(promise, params = {}) {
@@ -13,18 +13,23 @@ function setup(promise, params = {}) {
 
 describe('Rest Entry', () => {
   test('Entry update with tags works', async () => {
-    const { httpMock, adapterMock } = setup()
     const entityMock = cloneMock('entryWithTags')
     entityMock.sys.version = 2
+
+    const { httpMock, adapterMock } = setup(Promise.resolve({ data: entityMock }))
+
     const entity = wrapEntry((...args) => adapterMock.makeRequest(...args), entityMock)
-    entity.metadata.tags[0] = {
-      name: 'newname',
-      sys: entityMock.metadata.tags[0].sys,
-    }
+
+    entity.metadata.tags = entityMock.metadata.tags
+    entity.metadata.tags[0].sys.id = 'changed-link-target'
+
     return entity.update().then((response) => {
       expect(response.toPlainObject, 'response is wrapped').to.be.ok
-      expect(httpMock.put.args[0][1].metadata.tags[0].name).equals('newname', 'metadata is sent')
-      expect(httpMock.put.args[0][2].headers['X-Contentful-Version']).equals(
+      expect(httpMock.put.mock.calls[0][1].metadata.tags[0].sys.id).equals(
+        'changed-link-target',
+        'metadata is sent'
+      )
+      expect(httpMock.put.mock.calls[0][2].headers['X-Contentful-Version']).equals(
         2,
         'version header is sent'
       )
@@ -39,7 +44,7 @@ describe('Rest Entry', () => {
   test('API call createEntryWithId', async () => {
     const { httpMock, adapterMock, entityMock } = setup(Promise.resolve({}))
 
-    httpMock.put.returns(Promise.resolve({ data: entityMock }))
+    httpMock.put.mockReturnValue(Promise.resolve({ data: entityMock }))
 
     return adapterMock
       .makeRequest({
@@ -55,12 +60,12 @@ describe('Rest Entry', () => {
       })
       .then((r) => {
         expect(r).to.eql(entityMock)
-        expect(httpMock.put.args[0][0]).to.eql(
+        expect(httpMock.put.mock.calls[0][0]).to.eql(
           '/spaces/id/environments/id/entries/entryId',
           'entry id is sent'
         )
-        expect(httpMock.put.args[0][1]).to.eql(entityMock, 'data is sent')
-        expect(httpMock.put.args[0][2].headers['X-Contentful-Content-Type']).to.eql(
+        expect(httpMock.put.mock.calls[0][1]).to.eql(entityMock, 'data is sent')
+        expect(httpMock.put.mock.calls[0][2].headers['X-Contentful-Content-Type']).to.eql(
           'contentTypeId',
           'content type is specified'
         )
diff --git a/test/unit/adapters/REST/endpoints/environment-template-test.ts b/test/unit/adapters/REST/endpoints/environment-template.test.ts
similarity index 80%
rename from test/unit/adapters/REST/endpoints/environment-template-test.ts
rename to test/unit/adapters/REST/endpoints/environment-template.test.ts
index a27f7af3cb..403d58d5d2 100644
--- a/test/unit/adapters/REST/endpoints/environment-template-test.ts
+++ b/test/unit/adapters/REST/endpoints/environment-template.test.ts
@@ -1,6 +1,5 @@
-import { describe } from 'mocha'
+import { describe, expect } from 'vitest'
 import { cloneMock } from '../../../mocks/entities'
-import { expect } from 'chai'
 import setupRestAdapter from '../helpers/setupRestAdapter'
 
 describe('Environment Template', async () => {
@@ -17,7 +16,7 @@ describe('Environment Template', async () => {
 
   actions.forEach((action) => {
     it(`propagates custom headers for ${action.name} request`, async () => {
-      const { adapterMock, httpMock } = setupRestAdapter()
+      const { adapterMock, httpMock } = setupRestAdapter(Promise.resolve({}))
 
       const entityMock = cloneMock(mockName)
 
@@ -30,7 +29,7 @@ describe('Environment Template', async () => {
         userAgent: 'mockedAgent',
       })
 
-      expect(httpMock[action.httpMethod].args[0][2].headers['X-Test']).equals('test header')
+      expect(httpMock[action.httpMethod].mock.calls[0][2].headers['X-Test']).equals('test header')
     })
   })
 })
diff --git a/test/unit/adapters/REST/endpoints/extension-test.js b/test/unit/adapters/REST/endpoints/extension.test.ts
similarity index 82%
rename from test/unit/adapters/REST/endpoints/extension-test.js
rename to test/unit/adapters/REST/endpoints/extension.test.ts
index 16759e3b7c..8b029e988f 100644
--- a/test/unit/adapters/REST/endpoints/extension-test.js
+++ b/test/unit/adapters/REST/endpoints/extension.test.ts
@@ -1,4 +1,4 @@
-import { describe } from 'mocha'
+import { describe } from 'vitest'
 import { reusableEntityUpdateTest } from '../reusable-tests/update'
 
 describe('Rest Extension', () => {
diff --git a/test/unit/adapters/REST/endpoints/organization-membership-test.js b/test/unit/adapters/REST/endpoints/organization-membership.test.ts
similarity index 83%
rename from test/unit/adapters/REST/endpoints/organization-membership-test.js
rename to test/unit/adapters/REST/endpoints/organization-membership.test.ts
index ca27c49ddd..2ab1ce6f97 100644
--- a/test/unit/adapters/REST/endpoints/organization-membership-test.js
+++ b/test/unit/adapters/REST/endpoints/organization-membership.test.ts
@@ -1,5 +1,4 @@
-import { expect } from 'chai'
-import { describe, test } from 'mocha'
+import { describe, test, expect } from 'vitest'
 import { cloneMock } from '../../../mocks/entities'
 import { wrapOrganizationMembership } from '../../../../../lib/entities/organization-membership'
 import setupRestAdapter from '../helpers/setupRestAdapter'
@@ -13,7 +12,7 @@ function setup(promise, params = {}) {
 
 describe('Rest Organization Membership', () => {
   test('OrganizationMembership delete', async () => {
-    const { httpMock, entityMock, adapterMock } = setup()
+    const { httpMock, entityMock, adapterMock } = setup(Promise.resolve({}))
     entityMock.sys.version = 2
     const entity = wrapOrganizationMembership(
       (...args) => adapterMock.makeRequest(...args),
@@ -21,7 +20,7 @@ describe('Rest Organization Membership', () => {
       'org-id'
     )
     return entity.delete().then((response) => {
-      expect(httpMock.delete.args[0][0]).equals(
+      expect(httpMock.delete.mock.calls[0][0]).equals(
         `/organizations/org-id/organization_memberships/${entityMock.sys.id}`,
         'url is correct'
       )
diff --git a/test/unit/adapters/REST/endpoints/team-membership-test.js b/test/unit/adapters/REST/endpoints/team-membership.test.ts
similarity index 61%
rename from test/unit/adapters/REST/endpoints/team-membership-test.js
rename to test/unit/adapters/REST/endpoints/team-membership.test.ts
index 1b2975b1a9..b7cdfbe42d 100644
--- a/test/unit/adapters/REST/endpoints/team-membership-test.js
+++ b/test/unit/adapters/REST/endpoints/team-membership.test.ts
@@ -1,5 +1,4 @@
-import { expect } from 'chai'
-import { describe, test } from 'mocha'
+import { expect, describe, test } from 'vitest'
 import { cloneMock } from '../../../mocks/entities'
 import { wrapTeamMembership } from '../../../../../lib/entities/team-membership'
 import setupRestAdapter from '../helpers/setupRestAdapter'
@@ -13,18 +12,18 @@ function setup(promise, params = {}) {
 
 describe('Rest Team Membership', () => {
   test('TeamMembership update', async () => {
-    const { httpMock, entityMock, adapterMock } = setup()
+    const { httpMock, entityMock, adapterMock } = setup(Promise.resolve({}))
     entityMock.sys.version = 2
-    entityMock.sys.team = { sys: { id: 'team1' } }
+    entityMock.sys.team = { sys: { id: 'team1', linkType: 'Team', type: 'Link' } }
     const entity = wrapTeamMembership((...args) => adapterMock.makeRequest(...args), entityMock)
     entity.admin = true
     return entity.update().then((response) => {
       expect(response.toPlainObject, 'response is wrapped').to.be.ok
-      expect(httpMock.put.args[0][0]).equals(
-        `/organizations/org-id/teams/team1/team_memberships/${entityMock.sys.id}`,
+      expect(httpMock.put.mock.calls[0][0]).equals(
+        `/organizations/mock-organization-id/teams/team1/team_memberships/${entityMock.sys.id}`,
         'url is correct'
       )
-      expect(httpMock.put.args[0][2].headers['X-Contentful-Version']).equals(
+      expect(httpMock.put.mock.calls[0][2].headers['X-Contentful-Version']).equals(
         2,
         'version header is sent'
       )
@@ -37,13 +36,13 @@ describe('Rest Team Membership', () => {
   })
 
   test('TeamMembership delete', async () => {
-    const { httpMock, entityMock, adapterMock } = setup()
+    const { httpMock, entityMock, adapterMock } = setup(Promise.resolve({}))
     entityMock.sys.version = 2
-    entityMock.sys.team = { sys: { id: 'team1' } }
+    entityMock.sys.team = { sys: { id: 'team1', linkType: 'Team', type: 'Link' } }
     const entity = wrapTeamMembership((...args) => adapterMock.makeRequest(...args), entityMock)
     return entity.delete().then((response) => {
-      expect(httpMock.delete.args[0][0]).equals(
-        `/organizations/org-id/teams/team1/team_memberships/${entityMock.sys.id}`,
+      expect(httpMock.delete.mock.calls[0][0]).equals(
+        `/organizations/mock-organization-id/teams/team1/team_memberships/${entityMock.sys.id}`,
         'url is correct'
       )
       return {
diff --git a/test/unit/adapters/REST/endpoints/team-test.js b/test/unit/adapters/REST/endpoints/team.test.ts
similarity index 68%
rename from test/unit/adapters/REST/endpoints/team-test.js
rename to test/unit/adapters/REST/endpoints/team.test.ts
index 42ed4af640..07ca6a95fa 100644
--- a/test/unit/adapters/REST/endpoints/team-test.js
+++ b/test/unit/adapters/REST/endpoints/team.test.ts
@@ -1,5 +1,4 @@
-import { expect } from 'chai'
-import { describe, test } from 'mocha'
+import { expect, describe, test } from 'vitest'
 import { cloneMock } from '../../../mocks/entities'
 import { wrapTeam } from '../../../../../lib/entities/team'
 import setupRestAdapter from '../helpers/setupRestAdapter'
@@ -13,17 +12,17 @@ function setup(promise, params = {}) {
 
 describe('Rest Team', () => {
   test('Team update', async () => {
-    const { httpMock, adapterMock, entityMock } = setup()
+    const { httpMock, adapterMock, entityMock } = setup(Promise.resolve({}))
     entityMock.sys.version = 2
     const entity = wrapTeam((...args) => adapterMock.makeRequest(...args), entityMock)
     entity.description = 'new description'
     return entity.update().then((response) => {
       expect(response.toPlainObject, 'response is wrapped').to.be.ok
-      expect(httpMock.put.args[0][0]).equals(
-        `/organizations/org-id/teams/${entityMock.sys.id}`,
+      expect(httpMock.put.mock.calls[0][0]).equals(
+        `/organizations/mock-organization-id/teams/${entityMock.sys.id}`,
         'url is correct'
       )
-      expect(httpMock.put.args[0][2].headers['X-Contentful-Version']).equals(
+      expect(httpMock.put.mock.calls[0][2].headers['X-Contentful-Version']).equals(
         2,
         'version header is sent'
       )
@@ -36,12 +35,12 @@ describe('Rest Team', () => {
   })
 
   test('Team delete', async () => {
-    const { httpMock, entityMock, adapterMock } = setup()
+    const { httpMock, entityMock, adapterMock } = setup(Promise.resolve({}))
     entityMock.sys.version = 2
     const entity = wrapTeam((...args) => adapterMock.makeRequest(...args), entityMock)
     return entity.delete().then((response) => {
-      expect(httpMock.delete.args[0][0]).equals(
-        `/organizations/org-id/teams/${entityMock.sys.id}`,
+      expect(httpMock.delete.mock.calls[0][0]).equals(
+        `/organizations/mock-organization-id/teams/${entityMock.sys.id}`,
         'url is correct'
       )
       return {
diff --git a/test/unit/adapters/REST/endpoints/ui-config-test.js b/test/unit/adapters/REST/endpoints/ui-config.test.ts
similarity index 69%
rename from test/unit/adapters/REST/endpoints/ui-config-test.js
rename to test/unit/adapters/REST/endpoints/ui-config.test.ts
index 88d6c0dd45..86cf934bad 100644
--- a/test/unit/adapters/REST/endpoints/ui-config-test.js
+++ b/test/unit/adapters/REST/endpoints/ui-config.test.ts
@@ -1,5 +1,4 @@
-import { expect } from 'chai'
-import { describe, test } from 'mocha'
+import { describe, test, expect } from 'vitest'
 import { wrapUIConfig } from '../../../../../lib/entities/ui-config'
 import { cloneMock } from '../../../mocks/entities'
 import setupRestAdapter from '../helpers/setupRestAdapter'
@@ -13,16 +12,16 @@ function setup(promise, params = {}) {
 
 describe('Rest UIConfig', () => {
   test('UIConfig update works', async () => {
-    const { httpMock, adapterMock } = setup()
+    const { httpMock, adapterMock } = setup(Promise.resolve({}))
     const entityMock = cloneMock('uiConfig')
     entityMock.sys.version = 2
     const entity = wrapUIConfig((...args) => adapterMock.makeRequest(...args), entityMock)
-    entity.entryListViews[0] = 'view'
+    entity.entryListViews = [{ id: 'view', title: 'View', views: [] }]
 
     return entity.update().then((response) => {
       expect(response.toPlainObject, 'response is wrapped').to.be.ok
-      expect(httpMock.put.args[0][1].entryListViews[0]).equals('view', 'metadata is sent')
-      expect(httpMock.put.args[0][2].headers['X-Contentful-Version']).equals(
+      expect(httpMock.put.mock.calls[0][1].entryListViews[0].id).equals('view', 'metadata is sent')
+      expect(httpMock.put.mock.calls[0][2].headers['X-Contentful-Version']).equals(
         2,
         'version header is sent'
       )
diff --git a/test/unit/adapters/REST/endpoints/upload-test.js b/test/unit/adapters/REST/endpoints/upload.test.ts
similarity index 74%
rename from test/unit/adapters/REST/endpoints/upload-test.js
rename to test/unit/adapters/REST/endpoints/upload.test.ts
index 309018b090..194e758bf9 100644
--- a/test/unit/adapters/REST/endpoints/upload-test.js
+++ b/test/unit/adapters/REST/endpoints/upload.test.ts
@@ -1,6 +1,6 @@
-import { describe, test } from 'mocha'
+import { describe, test, expect } from 'vitest'
 import { cloneMock } from '../../../mocks/entities'
-import { expect } from 'chai'
+
 import setupRestAdapter from '../helpers/setupRestAdapter'
 
 function setup(promise, params = {}) {
@@ -29,9 +29,11 @@ describe('Rest Upload', async () => {
         },
       })
       .then(() => {
-        expect(httpMock.post.args[0][0]).equals('/spaces/id/environments/envId/uploads')
-        expect(httpMock.post.args[0][2].headers['Content-Type']).equals('application/octet-stream')
-        expect(httpMock.post.args[0][1]).equals(
+        expect(httpMock.post.mock.calls[0][0]).equals('/spaces/id/environments/envId/uploads')
+        expect(httpMock.post.mock.calls[0][2].headers['Content-Type']).equals(
+          'application/octet-stream'
+        )
+        expect(httpMock.post.mock.calls[0][1]).equals(
           '<svg><path fill="red" d="M50 50h150v50H50z"/></svg>',
           'uploads file to upload endpoint'
         )
@@ -55,9 +57,11 @@ describe('Rest Upload', async () => {
         },
       })
       .then(() => {
-        expect(httpMock.post.args[0][0]).equals('/spaces/id/uploads')
-        expect(httpMock.post.args[0][2].headers['Content-Type']).equals('application/octet-stream')
-        expect(httpMock.post.args[0][1]).equals(
+        expect(httpMock.post.mock.calls[0][0]).equals('/spaces/id/uploads')
+        expect(httpMock.post.mock.calls[0][2].headers['Content-Type']).equals(
+          'application/octet-stream'
+        )
+        expect(httpMock.post.mock.calls[0][1]).equals(
           '<svg><path fill="red" d="M50 50h150v50H50z"/></svg>',
           'uploads file to upload endpoint'
         )
@@ -79,8 +83,10 @@ describe('Rest Upload', async () => {
         },
       })
       .then(() => {
-        expect(httpMock.post.args[0][2].headers['Content-Type']).equals('application/octet-stream')
-        expect(httpMock.post.args[0][1]).equals(
+        expect(httpMock.post.mock.calls[0][2].headers['Content-Type']).equals(
+          'application/octet-stream'
+        )
+        expect(httpMock.post.mock.calls[0][1]).equals(
           '<svg><path fill="red" d="M50 50h150v50H50z"/></svg>',
           'uploads file to upload endpoint'
         )
diff --git a/test/unit/adapters/REST/endpoints/user-ui-config-test.js b/test/unit/adapters/REST/endpoints/user-ui-config.test.ts
similarity index 69%
rename from test/unit/adapters/REST/endpoints/user-ui-config-test.js
rename to test/unit/adapters/REST/endpoints/user-ui-config.test.ts
index 2b9e621759..dbe3c96a55 100644
--- a/test/unit/adapters/REST/endpoints/user-ui-config-test.js
+++ b/test/unit/adapters/REST/endpoints/user-ui-config.test.ts
@@ -1,5 +1,4 @@
-import { expect } from 'chai'
-import { describe, test } from 'mocha'
+import { describe, test, expect } from 'vitest'
 import { wrapUIConfig } from '../../../../../lib/entities/ui-config'
 import { cloneMock } from '../../../mocks/entities'
 import setupRestAdapter from '../helpers/setupRestAdapter'
@@ -13,16 +12,16 @@ function setup(promise, params = {}) {
 
 describe('Rest UserUIConfig', () => {
   test('UIConfig update works', async () => {
-    const { httpMock, adapterMock } = setup()
+    const { httpMock, adapterMock } = setup(Promise.resolve({}))
     const entityMock = cloneMock('userUIConfig')
     entityMock.sys.version = 2
     const entity = wrapUIConfig((...args) => adapterMock.makeRequest(...args), entityMock)
-    entity.entryListViews[0] = 'view'
+    entity.entryListViews = [{ id: 'view', title: 'View', views: [] }]
 
     return entity.update().then((response) => {
       expect(response.toPlainObject, 'response is wrapped').to.be.ok
-      expect(httpMock.put.args[0][1].entryListViews[0]).equals('view', 'metadata is sent')
-      expect(httpMock.put.args[0][2].headers['X-Contentful-Version']).equals(
+      expect(httpMock.put.mock.calls[0][1].entryListViews[0]).equals('view', 'metadata is sent')
+      expect(httpMock.put.mock.calls[0][2].headers['X-Contentful-Version']).equals(
         2,
         'version header is sent'
       )
diff --git a/test/unit/adapters/REST/endpoints/utils-test.js b/test/unit/adapters/REST/endpoints/utils.test.ts
similarity index 90%
rename from test/unit/adapters/REST/endpoints/utils-test.js
rename to test/unit/adapters/REST/endpoints/utils.test.ts
index 9726c9cb55..87208b739b 100644
--- a/test/unit/adapters/REST/endpoints/utils-test.js
+++ b/test/unit/adapters/REST/endpoints/utils.test.ts
@@ -1,5 +1,4 @@
-import { expect } from 'chai'
-import { describe, it } from 'mocha'
+import { describe, it, expect } from 'vitest'
 import { normalizeSpaceId } from '../../../../../lib/adapters/REST/endpoints/utils'
 
 describe('normalizeSpaceId', () => {
diff --git a/test/unit/adapters/REST/endpoints/workflow-definition-test.ts b/test/unit/adapters/REST/endpoints/workflow-definition.test.ts
similarity index 86%
rename from test/unit/adapters/REST/endpoints/workflow-definition-test.ts
rename to test/unit/adapters/REST/endpoints/workflow-definition.test.ts
index 10f1c15436..432a9d941d 100644
--- a/test/unit/adapters/REST/endpoints/workflow-definition-test.ts
+++ b/test/unit/adapters/REST/endpoints/workflow-definition.test.ts
@@ -1,5 +1,4 @@
-import { expect } from 'chai'
-import { describe, test } from 'mocha'
+import { describe, test, expect } from 'vitest'
 import { cloneMock } from '../../../mocks/entities'
 import setupRestAdapter from '../helpers/setupRestAdapter'
 import {
@@ -28,11 +27,11 @@ describe('Rest Workflow Definition', () => {
     entity.description = 'new description'
     return entity.update().then((response) => {
       expect(response.toPlainObject, 'response is wrapped').to.be.ok
-      expect(httpMock.put.args[0][0]).equals(
+      expect(httpMock.put.mock.calls[0][0]).equals(
         `/spaces/${entityMock.sys.space.sys.id}/environments/${entityMock.sys.environment.sys.id}/workflow_definitions/${entityMock.sys.id}`,
         'url is correct'
       )
-      expect(httpMock.put.args[0][2].headers['X-Contentful-Version']).equals(
+      expect(httpMock.put.mock.calls[0][2].headers['X-Contentful-Version']).equals(
         2,
         'version header is sent'
       )
@@ -52,11 +51,11 @@ describe('Rest Workflow Definition', () => {
       entityMock
     )
     return entity.delete().then(() => {
-      expect(httpMock.delete.args[0][0]).equals(
+      expect(httpMock.delete.mock.calls[0][0]).equals(
         `/spaces/${entityMock.sys.space.sys.id}/environments/${entityMock.sys.environment.sys.id}/workflow_definitions/${entityMock.sys.id}`,
         'url is correct'
       )
-      expect(httpMock.delete.args[0][1].headers['X-Contentful-Version']).equals(
+      expect(httpMock.delete.mock.calls[0][1].headers['X-Contentful-Version']).equals(
         2,
         'version header is sent'
       )
diff --git a/test/unit/adapters/REST/helpers/setupRestAdapter.ts b/test/unit/adapters/REST/helpers/setupRestAdapter.ts
index 3b8bebbecf..acb5054068 100644
--- a/test/unit/adapters/REST/helpers/setupRestAdapter.ts
+++ b/test/unit/adapters/REST/helpers/setupRestAdapter.ts
@@ -1,9 +1,18 @@
-import { MockedFunction } from 'vitest'
+import { vi, MockedFunction } from 'vitest'
 import { RestAdapter } from '../../../../../lib/adapters/REST/rest-adapter'
 import setupHttpMock from '../../../mocks/http'
+import contentfulSdkCore from 'contentful-sdk-core'
 
 import { AxiosInstance, createHttpClient } from 'contentful-sdk-core'
 
+vi.mock('contentful-sdk-core', async (importOriginal) => {
+  const orig = await importOriginal<typeof contentfulSdkCore>()
+  return {
+    ...orig,
+    createHttpClient: vi.fn(),
+  }
+})
+
 const createHttpClientMock = <MockedFunction<typeof createHttpClient>>(<unknown>createHttpClient)
 
 export default function setupRestAdapter(httpPromise, params = {}) {
diff --git a/test/unit/adapters/REST/reusable-tests/update.js b/test/unit/adapters/REST/reusable-tests/update.ts
similarity index 52%
rename from test/unit/adapters/REST/reusable-tests/update.js
rename to test/unit/adapters/REST/reusable-tests/update.ts
index 96a7afd9cd..a79a935070 100644
--- a/test/unit/adapters/REST/reusable-tests/update.js
+++ b/test/unit/adapters/REST/reusable-tests/update.ts
@@ -1,16 +1,15 @@
 import setupRestAdapter from '../helpers/setupRestAdapter'
 import { cloneMock } from '../../../mocks/entities'
-import { expect } from 'chai'
-import { it } from 'mocha'
+import { expect, it } from 'vitest'
 
 export function reusableEntityUpdateTest(entityType, mockName) {
   it(`emits valid update request`, async () => {
-    const { adapterMock, httpMock } = setupRestAdapter()
-
     const entityMock = cloneMock(mockName)
     entityMock.name = 'updated name'
     entityMock.sys.version = 2
 
+    const { adapterMock, httpMock } = setupRestAdapter(Promise.resolve({ data: entityMock }))
+
     await adapterMock.makeRequest({
       entityType,
       action: 'update',
@@ -19,12 +18,15 @@ export function reusableEntityUpdateTest(entityType, mockName) {
       headers: { 'X-Test': 'test header' },
     })
 
-    expect(httpMock.put.args[0][1].name).equals('updated name', 'data is sent')
-    expect(httpMock.put.args[0][1].sys).equals(undefined, 'sys is removed')
-    expect(httpMock.put.args[0][2].headers['X-Contentful-Version']).equals(
+    expect(httpMock.put.mock.calls[0][1].name).equals('updated name', 'data is sent')
+    expect(httpMock.put.mock.calls[0][1].sys).equals(undefined, 'sys is removed')
+    expect(httpMock.put.mock.calls[0][2].headers['X-Contentful-Version']).equals(
       2,
       'version header is sent'
     )
-    expect(httpMock.put.args[0][2].headers['X-Test']).equals('test header', 'custom header is set')
+    expect(httpMock.put.mock.calls[0][2].headers['X-Test']).equals(
+      'test header',
+      'custom header is set'
+    )
   })
 }