Retrofit vs Ktor Client for Android

interface GithubApi {
    @GET("users/{user}/repos")
    suspend fun repos(@Path("user") user: String, @Query("per_page") perPage: Int = 30): List<RepoDto>
}
// val api = retrofit.create(GithubApi::class.java); api.repos("android")

val client = HttpClient(OkHttp) {                          // engine: OkHttp on Android
    install(ContentNegotiation) { json(Json { ignoreUnknownKeys = true }) }
    install(HttpTimeout) { requestTimeoutMillis = 15_000 }
    defaultRequest { url("https://api.github.com/") }
    expectSuccess = true                                    // throw on non-2xx
}

class GithubApi(private val client: HttpClient) {
    suspend fun repos(user: String, perPage: Int = 30): List<RepoDto> =
        client.get("users/$user/repos") { parameter("per_page", perPage) }.body()
}

@Test
fun `parses repos`() = runTest {
    val engine = MockEngine { request ->
        assertEquals("/users/android/repos", request.url.encodedPath)
        respond("""[{"id":1,"name":"nowinandroid"}]""", headers = headersOf(HttpHeaders.ContentType, "application/json"))
    }
    val client = HttpClient(engine) { install(ContentNegotiation) { json(Json { ignoreUnknownKeys = true }) } }
    val repos = GithubApi(client).repos("android")
    assertEquals("nowinandroid", repos.single().name)
}