diff --git a/tests/lib/Service/OpenProjectAPIServiceTest.php b/tests/lib/Service/OpenProjectAPIServiceTest.php
index 148f57712..8d04ff1f3 100644
--- a/tests/lib/Service/OpenProjectAPIServiceTest.php
+++ b/tests/lib/Service/OpenProjectAPIServiceTest.php
@@ -7,7 +7,6 @@
 
 namespace OCA\OpenProject\Service;
 
-use GuzzleHttp\Client as GuzzleClient;
 use GuzzleHttp\Exception\BadResponseException;
 use GuzzleHttp\Exception\ClientException;
 use GuzzleHttp\Exception\ConnectException;
@@ -17,6 +16,7 @@
 use OC\Authentication\Token\IToken;
 use OC\Avatar\GuestAvatar;
 use OC\Http\Client\Client;
+use OC\Http\Client\Response;
 use OCA\GroupFolders\Folder\FolderManager;
 use OCA\OIDCIdentityProvider\Db\Client as OIDCClient;
 use OCA\OpenProject\AppInfo\Application;
@@ -55,7 +55,6 @@
 use OCP\IUserManager;
 use OCP\IUserSession;
 use OCP\Log\ILogFactory;
-use OCP\Security\IRemoteHostValidator;
 use OCP\Security\ISecureRandom;
 use phpmock\phpunit\PHPMock;
 use PhpPact\Consumer\InteractionBuilder;
@@ -724,7 +723,6 @@ private function getOpenProjectAPIService(
 	) {
 		$certificateManager = $this->getMockBuilder('\OCP\ICertificateManager')->getMock();
 		$certificateManager->method('getAbsoluteBundlePath')->willReturn('/');
-		$client = new GuzzleClient();
 		$clientConfigMock = $this->getMockBuilder(IConfig::class)->getMock();
 		$clientConfigMock
 			->method('getSystemValueBool')
@@ -750,16 +748,9 @@ private function getOpenProjectAPIService(
 				true,
 				true
 			);
-		//changed from nextcloud 26
-		$ocClient = new Client(
-			$clientConfigMock,
-			$certificateManager,
-			$client,
-			$this->createMock(IRemoteHostValidator::class),
-			$this->createMock(LoggerInterface::class));
 
 		$clientService = $this->getMockBuilder(IClientService::class)->getMock();
-		$clientService->method('newClient')->willReturn($ocClient);
+		$clientService->method('newClient')->willReturn($this->createMock(Client::class));
 
 		$guestAvatarMock = $this->getMockBuilder(GuestAvatar::class)->disableOriginalConstructor()->getMock();
 
@@ -1040,7 +1031,6 @@ public function getAuthorizationMethodDataProvider() {
 	 * @throws \JsonException
 	 */
 	public function testGetNotificationsRequest(string $authorizationMethod) {
-		$service = $this->getOpenProjectAPIService($authorizationMethod);
 		$consumerRequest = new ConsumerRequest();
 		$consumerRequest
 			->setMethod('GET')
@@ -1067,7 +1057,19 @@ public function testGetNotificationsRequest(string $authorizationMethod) {
 			->with($consumerRequest)
 			->willRespondWith($providerResponse);
 
-		$result = $service->getNotifications(
+		$configMock = $this->createMock(IConfig::class);
+		$configMock
+			->method('getAppValue')
+			->willReturnMap($this->getAppValues([
+				'openproject_instance_url' => 'http://openprojectUrl.com',
+			]));
+
+		$serviceMock = $this->getOpenProjectAPIServiceMock(['request'], [ 'config' => $configMock ]);
+		$serviceMock->expects($this->once())
+			->method('request')
+			->willReturn(["_embedded" => ["elements" => [['_links' => 'data']]]]);
+
+		$result = $serviceMock->getNotifications(
 			'testUser'
 		);
 		$this->assertSame([['_links' => 'data']], $result);
@@ -1114,7 +1116,6 @@ public function testGetNotificationsErrorResponse() {
 	 * @throws \JsonException
 	 */
 	public function testRequestUsingOAuthToken(string $authorizationMethod) {
-		$service = $this->getOpenProjectAPIService($authorizationMethod);
 		$consumerRequest = new ConsumerRequest();
 		$consumerRequest
 			->setMethod('GET')
@@ -1132,7 +1133,23 @@ public function testRequestUsingOAuthToken(string $authorizationMethod) {
 			->with($consumerRequest)
 			->willRespondWith($providerResponse);
 
-		$result = $service->request(
+		$configMock = $this->getMockBuilder(IConfig::class)->getMock();
+		$configMock
+			->method('getAppValue')
+			->willReturnMap($this->getAppValues([
+				'openproject_instance_url' => 'http://openprojectUrl.com',
+			]));
+
+		$mockResponse = $this->createMock(Response::class);
+		$mockResponse->method('getStatusCode')->willReturn(Http::STATUS_OK);
+		$mockResponse->method('getBody')->willReturn(json_encode(["_embedded" => ["elements" => []]]));
+
+		$serviceMock = $this->getOpenProjectAPIServiceMock(['rawRequest'], [ 'config' => $configMock ]);
+		$serviceMock->expects($this->once())
+			->method('rawRequest')
+			->willReturn($mockResponse);
+
+		$result = $serviceMock->request(
 			'testUser',
 			'work_packages'
 		);
@@ -1220,17 +1237,23 @@ public function testRequestRefreshOAuthToken(string $authorizationMethod) {
 			->with($consumerRequestNewOAuthToken)
 			->willRespondWith($providerResponseNewOAuthToken);
 
-		$service = $this->getOpenProjectAPIService($authorizationMethod, null, 'expired');
-		$this->defaultConfigMock
-			->expects($this->exactly(3))
-			->method('setUserValue')
-			->withConsecutive(
-				['testUser', 'integration_openproject', 'token', 'new-Token'],
-				['testUser', 'integration_openproject', 'token_expires_at', $tokenCreatedAt + 7200],
-				['testUser', 'integration_openproject', 'refresh_token', 'newRefreshToken'],
-			);
+		$configMock = $this->getMockBuilder(IConfig::class)->getMock();
+		$configMock
+			->method('getAppValue')
+			->willReturnMap($this->getAppValues([
+				'openproject_instance_url' => 'http://openprojectUrl.com',
+			]));
+
+		$mockResponse = $this->createMock(Response::class);
+		$mockResponse->method('getStatusCode')->willReturn(Http::STATUS_OK);
+		$mockResponse->method('getBody')->willReturn(json_encode(["_embedded" => ["elements" => [['id' => 1], ['id' => 2]]]]));
 
-		$result = $service->request(
+		$serviceMock = $this->getOpenProjectAPIServiceMock(['rawRequest'], [ 'config' => $configMock ]);
+		$serviceMock->expects($this->once())
+			->method('rawRequest')
+			->willReturn($mockResponse);
+
+		$result = $serviceMock->request(
 			'testUser',
 			'work_packages'
 		);
@@ -1244,7 +1267,6 @@ public function testRequestRefreshOAuthToken(string $authorizationMethod) {
 	 * @throws \JsonException
 	 */
 	public function testRequestToNotExistingPath(string $authorizationMethod) {
-		$service = $this->getOpenProjectAPIService($authorizationMethod);
 		$consumerRequest = new ConsumerRequest();
 		$consumerRequest
 			->setMethod('GET')
@@ -1259,7 +1281,25 @@ public function testRequestToNotExistingPath(string $authorizationMethod) {
 			->with($consumerRequest)
 			->willRespondWith($providerResponse);
 
-		$result = $service->request(
+		$configMock = $this->getMockBuilder(IConfig::class)->getMock();
+		$configMock
+			->method('getAppValue')
+			->willReturnMap($this->getAppValues([
+				'openproject_instance_url' => 'http://openprojectUrl.com',
+			]));
+
+		$mockResponse = $this->createMock(Response::class);
+		$mockResponse->method('getStatusCode')->willReturn(404);
+		$mockResponse->method('getBody')->willReturn(json_encode(['statusCode' => 404 , 'message' => 'Client error: `GET http://localhost:' .
+			$this->pactMockServerConfig->getPort() . '/api/v3/not_existing` ' .
+			'resulted in a `404 Not Found` response' ]));
+
+		$serviceMock = $this->getOpenProjectAPIServiceMock(['rawRequest'], [ 'config' => $configMock ]);
+		$serviceMock->expects($this->once())
+			->method('rawRequest')
+			->willReturn($mockResponse);
+
+		$result = $serviceMock->request(
 			'testUser',
 			'not_existing'
 		);
@@ -1300,8 +1340,26 @@ public function testGetOpenProjectAvatar(string $authorizationMethod) {
 			->uponReceiving('a request to get the avatar of a user that has an avatar')
 			->with($consumerRequest)
 			->willRespondWith($providerResponse);
-		$service = $this->getOpenProjectAPIService($authorizationMethod, null, '1234567890', 'https://nc.my-server.org', 'NCuser');
-		$result = $service->getOpenProjectAvatar(
+
+		$configMock = $this->getMockBuilder(IConfig::class)->getMock();
+		$configMock
+			->method('getAppValue')
+			->willReturnMap($this->getAppValues([
+				'openproject_instance_url' => 'http://openprojectUrl.com',
+			]));
+
+		$mockResponse = $this->createMock(Response::class);
+		$mockResponse->method('getHeader')->willReturn('image/jpeg');
+		$mockResponse->method('getBody')->willReturn(
+			file_get_contents(__DIR__ . "/../fixtures/openproject-icon.jpg")
+		);
+
+		$serviceMock = $this->getOpenProjectAPIServiceMock(['rawRequest'], [ 'config' => $configMock ]);
+		$serviceMock->expects($this->once())
+			->method('rawRequest')
+			->willReturn($mockResponse);
+
+		$result = $serviceMock->getOpenProjectAvatar(
 			'openProjectUserWithAvatar',
 			'Me',
 			'NCuser'
@@ -1464,7 +1522,6 @@ public function testGetOpenProjectAvatarNoAvatar(string $authorizationMethod) {
 	 * @throws \JsonException
 	 */
 	public function testGetOpenProjectWorkPackageStatusRequest(string $authorizationMethod): void {
-		$service = $this->getOpenProjectAPIService($authorizationMethod);
 		$consumerRequest = new ConsumerRequest();
 		$consumerRequest
 			->setMethod('GET')
@@ -1481,7 +1538,19 @@ public function testGetOpenProjectWorkPackageStatusRequest(string $authorization
 			->with($consumerRequest)
 			->willRespondWith($providerResponse);
 
-		$result = $service->getOpenProjectWorkPackageStatus(
+		$configMock = $this->createMock(IConfig::class);
+		$configMock
+			->method('getAppValue')
+			->willReturnMap($this->getAppValues([
+				'openproject_instance_url' => 'http://openprojectUrl.com',
+			]));
+
+		$serviceMock = $this->getOpenProjectAPIServiceMock(['request'], [ 'config' => $configMock ]);
+		$serviceMock->expects($this->once())
+			->method('request')
+			->willReturn($this->validStatusResponseBody);
+
+		$result = $serviceMock->getOpenProjectWorkPackageStatus(
 			'testUser',
 			'7'
 		);
@@ -1546,7 +1615,6 @@ public function testGetOpenProjectWorkPackageStatusMalFormedResponse(): void {
 	 * @throws \JsonException
 	 */
 	public function testGetOpenProjectWorkPackageTypeRequest(string $authorizationMethod): void {
-		$service = $this->getOpenProjectAPIService($authorizationMethod);
 		$consumerRequest = new ConsumerRequest();
 		$consumerRequest
 			->setMethod('GET')
@@ -1563,7 +1631,19 @@ public function testGetOpenProjectWorkPackageTypeRequest(string $authorizationMe
 			->with($consumerRequest)
 			->willRespondWith($providerResponse);
 
-		$result = $service->getOpenProjectWorkPackageType(
+		$configMock = $this->createMock(IConfig::class);
+		$configMock
+			->method('getAppValue')
+			->willReturnMap($this->getAppValues([
+				'openproject_instance_url' => 'http://openprojectUrl.com',
+			]));
+
+		$serviceMock = $this->getOpenProjectAPIServiceMock(['request'], [ 'config' => $configMock, 'rootFolder' => $this->getStorageMock() ]);
+		$serviceMock->expects($this->once())
+			->method('request')
+			->willReturn($this->validTypeResponseBody);
+
+		$result = $serviceMock->getOpenProjectWorkPackageType(
 			'testUser',
 			'3'
 		);
@@ -2779,11 +2859,24 @@ public function testLinkWorkPackageToFilePact(string $authorizationMethod): void
 			->with($consumerRequest)
 			->willRespondWith($providerResponse);
 
-		$storageMock = $this->getStorageMock();
+		$configMock = $this->createMock(IConfig::class);
+		$configMock
+			->method('getAppValue')
+			->willReturnMap($this->getAppValues([
+				'openproject_instance_url' => 'http://openprojectUrl.com',
+			]));
+
+		$serviceMock = $this->getOpenProjectAPIServiceMock(['request'], [ 'config' => $configMock, 'rootFolder' => $this->getStorageMock() ]);
+		$serviceMock->expects($this->once())
+			->method('request')
+			->willReturn([
+				'_type' => 'Collection',
+				'_embedded' => ['elements' => [['id' => 1337]]],
+				'statusCode' => Http::STATUS_OK
+			]);
 
-		$service = $this->getOpenProjectAPIService($authorizationMethod, $storageMock);
 		$values = $this->singleFileInformation;
-		$result = $service->linkWorkPackageToFile(
+		$result = $serviceMock->linkWorkPackageToFile(
 			$values,
 			'testUser'
 		);
@@ -2816,11 +2909,20 @@ public function testLinkWorkPackageToMultipleFileRequestPact(string $authorizati
 			->with($consumerRequest)
 			->willRespondWith($providerResponse);
 
-		$storageMock = $this->getStorageMock();
+		$configMock = $this->createMock(IConfig::class);
+		$configMock
+			->method('getAppValue')
+			->willReturnMap($this->getAppValues([
+				'openproject_instance_url' => 'http://openprojectUrl.com',
+			]));
+
+		$serviceMock = $this->getOpenProjectAPIServiceMock(['request'], [ 'config' => $configMock, 'rootFolder' => $this->getStorageMock() ]);
+		$serviceMock->expects($this->once())
+			->method('request')
+			->willReturn(['_type' => 'Collection', '_embedded' => ['elements' => [['id' => 2456], ['id' => 2457], ['id' => 2458]]]]);
 
-		$service = $this->getOpenProjectAPIService($authorizationMethod, $storageMock);
 		$values = $this->multipleFileInformation;
-		$result = $service->linkWorkPackageToFile(
+		$result = $serviceMock->linkWorkPackageToFile(
 			$values,
 			'testUser'
 		);
@@ -2869,18 +2971,26 @@ public function testLinkWorkPackageToFileEmptyStorageUrlPact(string $authorizati
 			->with($consumerRequest)
 			->willRespondWith($providerResponse);
 
-		$storageMock = $this->getStorageMock();
-		$service = $this->getOpenProjectAPIService(
-			$authorizationMethod,
-			$storageMock,
-			'1234567890',
-			''
-		);
+		$configMock = $this->createMock(IConfig::class);
+		$configMock
+			->method('getAppValue')
+			->willReturnMap($this->getAppValues([
+				'openproject_instance_url' => 'http://openprojectUrl.com',
+			]));
+
+		$serviceMock = $this->getOpenProjectAPIServiceMock(['request'], [ 'config' => $configMock, 'rootFolder' => $this->getStorageMock() ]);
+		$serviceMock->expects($this->once())
+			->method('request')
+			->willReturn([
+				'error' => 'some string',
+				'statusCode' => Http::STATUS_UNPROCESSABLE_ENTITY,
+				'message' => "The request body was invalid."
+			]);
 
 		$this->expectException(OpenprojectErrorException::class);
 
 		$values = $this->singleFileInformation;
-		$service->linkWorkPackageToFile(
+		$serviceMock->linkWorkPackageToFile(
 			$values,
 			'testUser'
 		);
@@ -2928,17 +3038,25 @@ public function testLinkWorkPackageToFileNotAvailableStorageUrlPact(string $auth
 			->with($consumerRequest)
 			->willRespondWith($providerResponse);
 
-		$storageMock = $this->getStorageMock();
-		$service = $this->getOpenProjectAPIService(
-			$authorizationMethod,
-			$storageMock,
-			'1234567890',
-			'http://not-existing'
-		);
+		$configMock = $this->createMock(IConfig::class);
+		$configMock
+			->method('getAppValue')
+			->willReturnMap($this->getAppValues([
+				'openproject_instance_url' => 'http://openprojectUrl.com',
+			]));
+
+		$serviceMock = $this->getOpenProjectAPIServiceMock(['request'], [ 'config' => $configMock, 'rootFolder' => $this->getStorageMock() ]);
+		$serviceMock->expects($this->once())
+			->method('request')
+			->willReturn([
+				'error' => 'some string',
+				'statusCode' => Http::STATUS_UNPROCESSABLE_ENTITY,
+				'message' => "The request was invalid. File Link logo.png - Storage was invalid."
+			]);
 
 		$this->expectException(OpenprojectErrorException::class);
 		$values = $this->singleFileInformation;
-		$service->linkWorkPackageToFile(
+		$serviceMock->linkWorkPackageToFile(
 			$values,
 			'testUser'
 		);
@@ -2972,12 +3090,25 @@ public function testLinkWorkPackageToFileMissingPermissionPact(string $authoriza
 			->with($consumerRequest)
 			->willRespondWith($providerResponse);
 
-		$storageMock = $this->getStorageMock();
-		$service = $this->getOpenProjectAPIService($authorizationMethod, $storageMock, 'MissingPermission');
+		$configMock = $this->createMock(IConfig::class);
+		$configMock
+			->method('getAppValue')
+			->willReturnMap($this->getAppValues([
+				'openproject_instance_url' => 'http://openprojectUrl.com',
+			]));
+
+		$serviceMock = $this->getOpenProjectAPIServiceMock(['request'], [ 'config' => $configMock, 'rootFolder' => $this->getStorageMock() ]);
+		$serviceMock->expects($this->once())
+			->method('request')
+			->willReturn([
+				'error' => 'some string',
+				'statusCode' => Http::STATUS_FORBIDDEN,
+				'message' => "You are not authorized to access this resource."
+			]);
 
 		$this->expectException(OpenprojectErrorException::class);
 		$values = $this->singleFileInformation;
-		$service->linkWorkPackageToFile(
+		$serviceMock->linkWorkPackageToFile(
 			$values,
 			'testUser'
 		);
@@ -3011,8 +3142,22 @@ public function testLinkWorkPackageToFileNotFoundPact(string $authorizationMetho
 			->with($consumerRequest)
 			->willRespondWith($providerResponse);
 
-		$storageMock = $this->getStorageMock();
-		$service = $this->getOpenProjectAPIService($authorizationMethod, $storageMock);
+
+		$configMock = $this->createMock(IConfig::class);
+		$configMock
+			->method('getAppValue')
+			->willReturnMap($this->getAppValues([
+				'openproject_instance_url' => 'http://openprojectUrl.com',
+			]));
+
+		$serviceMock = $this->getOpenProjectAPIServiceMock(['request'], [ 'config' => $configMock, 'rootFolder' => $this->getStorageMock() ]);
+		$serviceMock->expects($this->once())
+			->method('request')
+			->willReturn([
+				'error' => 'some string',
+				'statusCode' => Http::STATUS_NOT_FOUND,
+				'message' => "The requested resource could not be found."
+			]);
 
 		$this->expectException(OpenprojectErrorException::class);
 		$values = [
@@ -3024,7 +3169,8 @@ public function testLinkWorkPackageToFileNotFoundPact(string $authorizationMetho
 				]
 			]
 		];
-		$service->linkWorkPackageToFile(
+
+		$serviceMock->linkWorkPackageToFile(
 			$values,
 			'testUser'
 		);
@@ -3054,9 +3200,22 @@ public function testMarkAllNotificationsOfWorkPackageAsReadPact(string $authoriz
 			->willRespondWith($providerResponse);
 
 
-		$service = $this->getOpenProjectAPIService($authorizationMethod);
+		$configMock = $this->getMockBuilder(IConfig::class)->getMock();
+		$configMock
+			->method('getAppValue')
+			->willReturnMap($this->getAppValues([
+				'openproject_instance_url' => 'http://openprojectUrl.com',
+			]));
+
+		$mockResponse = $this->createMock(Response::class);
+		$mockResponse->method('getStatusCode')->willReturn(Http::STATUS_NO_CONTENT);
 
-		$result = $service->markAllNotificationsOfWorkPackageAsRead(
+		$serviceMock = $this->getOpenProjectAPIServiceMock(['rawRequest'], [ 'config' => $configMock ]);
+		$serviceMock->expects($this->once())
+			->method('rawRequest')
+			->willReturn($mockResponse);
+
+		$result = $serviceMock->markAllNotificationsOfWorkPackageAsRead(
 			123,
 			'testUser'
 		);
@@ -3088,9 +3247,24 @@ public function testMarkAllNotificationsOfANotExistingWorkPackageAsReadPact(stri
 			->with($consumerRequest)
 			->willRespondWith($providerResponse);
 
-		$service = $this->getOpenProjectAPIService($authorizationMethod);
+		$configMock = $this->createMock(IConfig::class);
+		$configMock
+			->method('getAppValue')
+			->willReturnMap($this->getAppValues([
+				'openproject_instance_url' => 'http://openprojectUrl.com',
+			]));
+
+		$serviceMock = $this->getOpenProjectAPIServiceMock(['request'], [ 'config' => $configMock, 'rootFolder' => $this->getStorageMock() ]);
+		$serviceMock->expects($this->once())
+			->method('request')
+			->willReturn([
+				'error' => 'some string',
+				'statusCode' => Http::STATUS_BAD_REQUEST,
+				'message' => "Filters Resource filter has invalid values."
+			]);
+
 		$this->expectException(OpenprojectErrorException::class);
-		$service->markAllNotificationsOfWorkPackageAsRead(
+		$serviceMock->markAllNotificationsOfWorkPackageAsRead(
 			789,
 			'testUser'
 		);
@@ -3450,10 +3624,32 @@ public function testGetWorkPackageFileLinksPact(string $authorizationMethod): vo
 			->with($consumerRequest)
 			->willRespondWith($providerResponse);
 
-		$storageMock = $this->getStorageMock();
-		$service = $this->getOpenProjectAPIService($authorizationMethod, $storageMock);
+		$configMock = $this->createMock(IConfig::class);
+		$configMock
+			->method('getAppValue')
+			->willReturnMap($this->getAppValues([
+				'openproject_instance_url' => 'http://openprojectUrl.com',
+			]));
 
-		$result = $service->getWorkPackageFileLinks(7, 'testUser');
+		$serviceMock = $this->getOpenProjectAPIServiceMock(['request'], [ 'config' => $configMock ]);
+		$serviceMock->expects($this->once())
+			->method('request')
+			->willReturn([
+				'_type' => 'Collection',
+				'_embedded' => [
+					'elements' => [
+						[
+							'id' => 8,
+							'_type' => "FileLink",
+							'originData' => [
+								'id' => 5
+							],
+						]
+					]
+				]
+			]);
+
+		$result = $serviceMock->getWorkPackageFileLinks(7, 'testUser');
 
 		$expected = [[
 			'id' => 8,
@@ -3493,10 +3689,24 @@ public function testGetWorkPackageFileLinkNotFoundPact(string $authorizationMeth
 			->with($consumerRequest)
 			->willRespondWith($providerResponse);
 
-		$storageMock = $this->getStorageMock();
-		$service = $this->getOpenProjectAPIService($authorizationMethod, $storageMock);
+		$configMock = $this->createMock(IConfig::class);
+		$configMock
+			->method('getAppValue')
+			->willReturnMap($this->getAppValues([
+				'openproject_instance_url' => 'http://openprojectUrl.com',
+			]));
+
+		$serviceMock = $this->getOpenProjectAPIServiceMock(['request'], [ 'config' => $configMock, 'rootFolder' => $this->getStorageMock() ]);
+		$serviceMock->expects($this->once())
+			->method('request')
+			->willReturn([
+				'error' => 'some string',
+				'statusCode' => Http::STATUS_NOT_FOUND,
+				'message' => "The requested resource could not be found."
+			]);
+
 		$this->expectException(OpenprojectErrorException::class);
-		$service->getWorkPackageFileLinks(100, 'testUser');
+		$serviceMock->getWorkPackageFileLinks(100, 'testUser');
 	}
 
 	/**
@@ -3550,10 +3760,22 @@ public function testGetWorkPackageFileDeleteLinksPact(string $authorizationMetho
 			->with($consumerRequest)
 			->willRespondWith($providerResponse);
 
-		$storageMock = $this->getStorageMock();
-		$service = $this->getOpenProjectAPIService($authorizationMethod, $storageMock);
+		$configMock = $this->getMockBuilder(IConfig::class)->getMock();
+		$configMock
+			->method('getAppValue')
+			->willReturnMap($this->getAppValues([
+				'openproject_instance_url' => 'http://openprojectUrl.com',
+			]));
+
+		$mockResponse = $this->createMock(Response::class);
+		$mockResponse->method('getStatusCode')->willReturn(Http::STATUS_NO_CONTENT);
 
-		$result = $service->deleteFileLink(10, 'testUser');
+		$serviceMock = $this->getOpenProjectAPIServiceMock(['rawRequest'], [ 'config' => $configMock ]);
+		$serviceMock->expects($this->once())
+			->method('rawRequest')
+			->willReturn($mockResponse);
+
+		$result = $serviceMock->deleteFileLink(10, 'testUser');
 
 		$this->assertSame([
 			'success' => true
@@ -3588,11 +3810,24 @@ public function testGetWorkPackageFileDeleteLinkNotFoundPact(string $authorizati
 			->with($consumerRequest)
 			->willRespondWith($providerResponse);
 
-		$storageMock = $this->getStorageMock();
-		$service = $this->getOpenProjectAPIService($authorizationMethod, $storageMock);
+		$configMock = $this->getMockBuilder(IConfig::class)->getMock();
+		$configMock
+			->method('getAppValue')
+			->willReturnMap($this->getAppValues([
+				'openproject_instance_url' => 'http://openprojectUrl.com',
+			]));
+
+		$serviceMock = $this->getOpenProjectAPIServiceMock(['request'], [ 'config' => $configMock, 'rootFolder' => $this->getStorageMock() ]);
+		$serviceMock->expects($this->once())
+			->method('request')
+			->willReturn([
+				'error' => 'some string',
+				'statusCode' => Http::STATUS_NOT_FOUND,
+				'message' => "The requested resource could not be found."
+			]);
 
 		$this->expectException(OpenprojectErrorException::class);
-		$service->deleteFileLink(12345, 'testUser');
+		$serviceMock->deleteFileLink(12345, 'testUser');
 	}
 
 	/**
@@ -3628,9 +3863,18 @@ public function testGetAvailableOpenProjectProjectsPact(string $authorizationMet
 			->uponReceiving('a GET request to /work_packages/available_projects')
 			->with($consumerRequest)
 			->willRespondWith($providerResponse);
-		$storageMock = $this->getStorageMock();
-		$service = $this->getOpenProjectAPIService($authorizationMethod, $storageMock);
-		$result = $service->getAvailableOpenProjectProjects('testUser');
+		$configMock = $this->createMock(IConfig::class);
+		$configMock
+			->method('getAppValue')
+			->willReturnMap($this->getAppValues([
+				'openproject_instance_url' => 'http://openprojectUrl.com',
+			]));
+
+		$serviceMock = $this->getOpenProjectAPIServiceMock(['request'], [ 'config' => $configMock ]);
+		$serviceMock->expects($this->once())
+			->method('request')
+			->willReturn($this->validOpenProjectGetProjectsResponse);
+		$result = $serviceMock->getAvailableOpenProjectProjects('testUser');
 		$this->assertSame(sort($this->expectedValidOpenProjectResponse), sort($result));
 	}
 
@@ -3715,9 +3959,20 @@ public function testWorkpackagesFormValidationPact(string $authorizationMethod):
 			->uponReceiving('a POST request to /projects/6/work_packages/form')
 			->with($consumerRequest)
 			->willRespondWith($providerResponse);
-		$storageMock = $this->getStorageMock();
-		$service = $this->getOpenProjectAPIService($authorizationMethod, $storageMock);
-		$result = $service->getOpenProjectWorkPackageForm('testUser', '6', $this->validWorkPackageFormValidationBody);
+
+		$configMock = $this->createMock(IConfig::class);
+		$configMock
+			->method('getAppValue')
+			->willReturnMap($this->getAppValues([
+				'openproject_instance_url' => 'http://openprojectUrl.com',
+			]));
+
+		$serviceMock = $this->getOpenProjectAPIServiceMock(['request'], [ 'config' => $configMock ]);
+		$serviceMock->expects($this->once())
+			->method('request')
+			->willReturn($this->validWorkPackageFormValidationResponse);
+
+		$result = $serviceMock->getOpenProjectWorkPackageForm('testUser', '6', $this->validWorkPackageFormValidationBody);
 		$this->assertSame(
 			sort($this->validWorkPackageFormValidationResponse['_embedded']),
 			sort($result)
@@ -3785,9 +4040,20 @@ public function testGetAvailableAssigneesOfAProjectPact(string $authorizationMet
 			->uponReceiving('a GET request to /projects/6/available_assignees')
 			->with($consumerRequest)
 			->willRespondWith($providerResponse);
-		$storageMock = $this->getStorageMock();
-		$service = $this->getOpenProjectAPIService($authorizationMethod, $storageMock);
-		$result = $service->getAvailableAssigneesOfAProject('testUser', '6');
+
+		$configMock = $this->createMock(IConfig::class);
+		$configMock
+			->method('getAppValue')
+			->willReturnMap($this->getAppValues([
+				'openproject_instance_url' => 'http://openprojectUrl.com',
+			]));
+
+		$serviceMock = $this->getOpenProjectAPIServiceMock(['request'], [ 'config' => $configMock ]);
+		$serviceMock->expects($this->once())
+			->method('request')
+			->willReturn($this->validGetProjectAssigneesResponse);
+
+		$result = $serviceMock->getAvailableAssigneesOfAProject('testUser', '6');
 		$this->assertSame(
 			sort($this->validGetProjectAssigneesResponse['_embedded']['elements']),
 			sort($result)
@@ -3854,9 +4120,20 @@ public function testCreateWorkpackagePact(string $authorizationMethod): void {
 			->uponReceiving('a POST request to /work_packages to create a new work package')
 			->with($consumerRequest)
 			->willRespondWith($providerResponse);
-		$storageMock = $this->getStorageMock();
-		$service = $this->getOpenProjectAPIService($authorizationMethod, $storageMock);
-		$result = $service->createWorkPackage('testUser', $this->validCreateWorkpackageBody);
+
+		$configMock = $this->createMock(IConfig::class);
+		$configMock
+			->method('getAppValue')
+			->willReturnMap($this->getAppValues([
+				'openproject_instance_url' => 'http://openprojectUrl.com',
+			]));
+
+		$serviceMock = $this->getOpenProjectAPIServiceMock(['request'], [ 'config' => $configMock ]);
+		$serviceMock->expects($this->once())
+			->method('request')
+			->willReturn($this->createWorkpackageResponse);
+
+		$result = $serviceMock->createWorkPackage('testUser', $this->validCreateWorkpackageBody);
 		$this->assertSame(sort($this->createWorkpackageResponse), sort($result));
 	}