How can i mock a multiple page response?

[TheBestPessimist]

Hello,

Sample repro here: https://github.com/TheBestPessimist/Youtube-Subscriptions-Mailer/blob/2bf38ec27b2841102e3e1431b6d318bb378ccd0a/src/test/kotlin/land/tbp/youtube/SubscriptionsFetcherTest.kt#L214-L220

I am trying to test my integration with the Youtube API.
For that one i'm creating a mockHttpTransport with a mockResponse (or a mockRequest, the same issue presented below arises):

        val mockHttpTransport = MockHttpTransport.Builder()
//            .setLowLevelHttpRequest(mockRequest)
            .setLowLevelHttpResponse(mockResponse)
            .build()

        val youtube = YouTube.Builder(
            mockHttpTransport,
            mockGoogleCredential.jsonFactory,
            mockGoogleCredential
        ).build()

I want to get all my subscriptions, but they are more than 50 so I get a paged response ("nextPageToken": "CAUQAA"), so i need to make a second request to execute:

        val request = youtube
            .subscriptions()
            .list(listOf("snippet", "contentDetails"))
            .setMaxResults(5000)
            .setMine(true)
            .setFields("*")
            .setPrettyPrint(true)

        val responseWhichReturnsTheCorrectSubscriptionListPage: SubscriptionListResponse = request.execute()
        println(responseWhichReturnsTheCorrectSubscriptionListPage)

  val responseWhichThrowsIAE: SubscriptionListResponse = request.setPageToken("CAUQAA").execute()
        println(responseWhichThrowsIAE)

Q1: why can't i return the same mock response multiple times? the second iteration throws java.lang.IllegalArgumentException: no JSON input found
Q2: How can i pass multiple different mockResponses to the transport, to simulate that i have to fetch multiple pages from youtube?

I have already tried searching on Stackoverflow, but i had little success: https://stackoverflow.com/search?tab=votes&q=%5bgoogle-cloud-platform%5d%20%20mock.

[TheBestPessimist]

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