unit-testing - Kotlin Mockito NullPointerException

Question

有类：

@Singleton
class Exchange(
    @Client("\${exchange.rest.url}") @Inject val httpClient: RxHttpClient
) : Exchange {

    override suspend fun getSymbols(): List<String> {
        val response = httpClient.retrieve(GET<String>("/someurl/symbols"), ExchangeInfo::class.java).awaitFirst()
        return response.data
            .map { it.symbol }.toList()
    }

}

@Introspected
@JsonIgnoreProperties(ignoreUnknown = true)
class ExchangeInfo(
    val data: List<Symbol>
)

@Introspected
@JsonIgnoreProperties(ignoreUnknown = true)
data class Symbol(
    val symbol: String
)

我想测试这个功能getSymbols()

我正在写一个测试类：

import new.project.ExchangeInfo
import new.project.SpotSymbol
import io.micronaut.http.HttpRequest
import io.micronaut.http.client.RxHttpClient
import io.reactivex.Emitter
import io.reactivex.Flowable
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.reactive.awaitFirst
import kotlinx.coroutines.runBlocking
import kotlinx.coroutines.withContext
import okhttp3.internal.immutableListOf
import org.junit.jupiter.api.Test
import org.mockito.Mockito.mock
import org.mockito.kotlin.whenever

class ExchangeTest {

    @Test
    fun getSymbolsTest() = runBlocking {
        //the answer I want to receive
        val response: Flowable<ExchangeInfo> = Flowable.generate<ExchangeInfo, String>(
            java.util.concurrent.Callable<String> { -> "symbol" },
            io.reactivex.functions.BiConsumer<String, Emitter<ExchangeInfo>> { t1, t2 -> }
        )

        val httpClient = mock(RxHttpClient::class.java)

        whenever(httpClient.retrieve(HttpRequest.GET<String>("/someurl/symbols"), ExchangeInfo::class.java))
            .thenReturn(response)

        val exchange = Exchange(httpClient)
        //calling the tested method
        val result = exchange.getSymbols()

        assert(immutableListOf("symbol") == result)
    }

}

运行测试时，我得到：

java.lang.NullPointerException: httpClient.retrieve (GET <… ExchangeInfo :: class.java) must not be null

你能告诉我如何正确模拟httpClient吗？

标签： unit-testingkotlinnullpointerexceptionmockingmockito

Answer 1

有必要这样做：doReturn(Flowable.just(ExchangeInfo)).when(httpClient).retrieve(any<HttpRequest<String>>(), any<Class<Any>>())