I m trying to test ktor but got this error ```SLF4J Failed t

Question

I m trying to test ktor but got this error ```SLF4J Failed to load class org slf4j impl StaticLoggerBinder SLF4J Defaulting to no operation NOP logger implementation SLF4J See for further details No transformation found class io ktor utils io ByteBufferChannel gt class kotlin collections List with response from status 202 Accepted response headers Content Type application json io ktor client call NoTransformationFoundException No transformation found class io ktor utils io ByteBufferChannel gt class kotlin collections List with response from status 202 Accepted response headers Content Type application json at app io ktor client call HttpClientCall bodyNullable HttpClientCall kt 93 at app jhonatan sabadi combustivel datasource client fuel FuelClient getFuels FuelClient kt 45 at app jhonatan sabadi combustivel datasource client fuel FuelClient$getFuels$1 invokeSuspend FuelClient kt at app kotlin coroutines jvm internal BaseContinuationImpl resumeWith ContinuationImpl kt 33 at app kotlinx coroutines DispatchedTask run DispatchedTask kt 106 at app kotlinx coroutines EventLoopImplBase processNextEvent EventLoop common kt 284 at app kotlinx coroutines BlockingCoroutine joinBlocking Builders kt 85 at app kotlinx coroutines BuildersKt BuildersKt runBlocking Builders kt 59 at app kotlinx coroutines BuildersKt runBlocking Unknown Source at app kotlinx coroutines BuildersKt BuildersKt runBlocking$default Builders kt 38 at app kotlinx coroutines BuildersKt runBlocking$default Unknown Source at app client FuelClientTest receive success when get fuels list FuelClientTest kt 99 at java base 11 0 14 jdk internal reflect NativeMethodAccessorImpl invoke0 Native Method at java base 11 0 14 jdk internal reflect NativeMethodAccessorImpl invoke NativeMethodAccessorImpl java 62 at java base 11 0 14 jdk internal reflect DelegatingMethodAccessorImpl invoke DelegatingMethodAccessorImpl java 43 at java base 11 0 14 java lang reflect Method invoke Method java 566 at app org junit runners model FrameworkMethod$1 runReflectiveCall FrameworkMethod java 59 at app org junit internal runners model ReflectiveCallable run ReflectiveCallable java 12 at app org junit runners model FrameworkMethod invokeExplosively FrameworkMethod java 56 at app org junit internal runners statements InvokeMethod evaluate InvokeMethod java 17 at app org junit runners ParentRunner$3 evaluate ParentRunner java 306 at app org junit runners BlockJUnit4ClassRunner$1 evaluate BlockJUnit4ClassRunner java 100 at app org junit runners ParentRunner runLeaf ParentRunner java 366 at app org junit runners BlockJUnit4ClassRunner runChild BlockJUnit4ClassRunner java 103 at app org junit runners BlockJUnit4ClassRunner runChild BlockJUnit4ClassRunner java 63 at app org junit runners ParentRunner$4 run ParentRunner java 331 at app org junit runners ParentRunner$1 schedule ParentRunner java 79 at app org junit runners ParentRunner runChildren ParentRunner java 329 at app org junit runners ParentRunner access$100 ParentRunner java 66 at app org junit runners ParentRunner$2 evaluate ParentRunner java 293 at app org junit runners ParentRunner$3 evaluate ParentRunner java 306 at app org junit runners ParentRunner run ParentRunner java 413 at org gradle api internal tasks testing junit JUnitTestClassExecutor runTestClass JUnitTestClassExecutor java 110 at org gradle api internal tasks testing junit JUnitTestClassExecutor execute JUnitTestClassExecutor java 58 at org gradle api internal tasks testing junit JUnitTestClassExecutor execute JUnitTestClassExecutor java 38 at org gradle api internal tasks testing junit AbstractJUnitTestClassProcessor processTestClass AbstractJUnitTestClassProcessor java 62 at org gradle api internal tasks testing SuiteTestClassProcessor processTestClass SuiteTestClassProcessor java 51 at java base 11 0 14 jdk internal reflect NativeMethodAccessorImpl invoke0 Native Method at java base 11 0 14 jdk internal reflect NativeMethodAccessorImpl invoke NativeMethodAccessorImpl java 62 at java base 11 0 14 jdk internal reflect DelegatingMethodAccessorImpl invoke DelegatingMethodAccessorImpl java 43 at java base 11 0 14 java lang reflect Method invoke Method java 566 at org gradle internal dispatch ReflectionDispatch dispatch ReflectionDispatch java 36 at org gradle internal dispatch ReflectionDispatch dispatch ReflectionDispatch java 24 at org gradle internal dispatch ContextClassLoaderDispatch dispatch ContextClassLoaderDispatch java 33 at org gradle internal dispatch ProxyDispatchAdapter$DispatchingInvocationHandler invoke ProxyDispatchAdapter java 94 at com sun proxy $Proxy2 processTestClass Unknown Source at org gradle api internal tasks testing worker TestWorker$2 run TestWorker java 176 at org gradle api internal tasks testing worker TestWorker executeAndMaintainThreadName TestWorker java 129 at org gradle api internal tasks testing worker TestWorker execute TestWorker java 100 at org gradle api internal tasks testing worker TestWorker execute TestWorker java 60 at org gradle process internal worker child ActionExecutionWorker execute ActionExecutionWorker java 56 at org gradle process internal worker child SystemApplicationClassLoaderWorker call SystemApplicationClassLoaderWorker java 133 at org gradle process internal worker child SystemApplicationClassLoaderWorker call SystemApplicationClassLoaderWorker java 71 at app worker org gradle process internal worker GradleWorkerMain run GradleWorkerMain java 69 at app worker org gradle process internal worker GradleWorkerMain main GradleWorkerMain java 74 ``` My test ``` private val mockEngine = MockEngine respond content = ByteReadChannel jsonResponse status = HttpStatusCode Accepted headers = headersOf HttpHeaders ContentType application json private val httClient = HttpClient mockEngine private val fuelClient = FuelClient httClient Test fun `receive success when get fuels list` = runTest val fuels = fuelClient getFuels FuelRequestParams state = RIO DE JANEIRO val fuel = fuels 0 val expectedCnpj = 04 041 907 0001 50 assertEquals expectedCnpj fuel cnpj ``` My client ``` override suspend fun getFuels fuelRequestParams FuelRequestParams List lt FuelDto gt val response = httpClient get Urls Fuel base url parameter Urls Fuel Params state fuelRequestParams state parameter Urls Fuel Params city fuelRequestParams city parameter Urls Fuel Params neighbor fuelRequestParams neighbor return response body ``` client ```httpClient install ContentNegotiation json Json prettyPrint = true isLenient = true ignoreUnknownKeys = true defaultRequest url Urls getBaseUrl UrlEnv DEV ```

sindrenm · Answer

You should add one of the several SLF4J implementations as Ktor uses their APIs to log stuff on the JVM Check out <https ktor io docs client logging html|https ktor io docs client logging html> for more info

sindrenm · Answer

For example you can add the org slf4j slf4j simple dependency which logs to the console or slf4j android which logs using LogCat on Android

Chrimaeon · Answer

You cannot `respond` a ByteReadChannel if you set the header to `application json` and use the JSON content negotiation Return a string that could be serialized < sindrenm> the logger is just a warning KTOR will fallback to the NOP logger

Chrimaeon · Answer

Also please use the a thread if you post code snippets

Jhonatan Sabadi · Answer

Finally i found a solution I was use a Builder class to create httpclient but not using on unit test

Jhonatan Sabadi · Answer

I started to receive httpEngine on builder

sindrenm · Answer

Oh my bad I didn t see the actual error in the stack trace half blame being on my phone sweat smile

Jhonatan Sabadi · Answer

Now ia can respond with body lt Type gt and get test passed

Jhonatan Sabadi · Answer

Its ok rsrs thank you all for trying to help me