Playfarmework testing: Upload file with Fake Request and mulipartFormData

Question

I'm trying to unit test a file upload through multipartFormData and returning status 200 if it returns back the uploaded url. However, I keep getting status 400 and unsure why its been unsucessful.

I've found online of the call needs to be writeable and have included a writeable class which i've imported as lazy val

"return a 200 if successful" in new SetUp {
      val fakeFileName = "testImage.png"
      val fakeUploadImageUrl = "https://s3.fakeImageUrl.png"
      val imageFile = new File(fakeFileName)
      val tempFile = TemporaryFile(imageFile)
      val multipartFormData = new MultipartFormData(
        dataParts = Map(),
        files = Seq(FilePart[TemporaryFile]("file", fakeFileName, Some("text/plain"), tempFile)),
        badParts = Seq()
      )

      when(imageService.uploadWebImage(any(), any())).thenReturn(Future.successful(fakeUploadImageUrl))

      val request = FakeRequest(HttpVerbs.POST, s"/internal/challengesv2/v1/instances/image/$fakeFileName")
        .withBody(multipartFormData)

      val response = testController.uploadImage(fakeFileName).apply(request)

      assert(status(response.run()) === 200)
      assert(contentAsJson(response.run()) === Json.toJson(fakeUploadImageUrl))
}

expect 200 but returning 400