protocol: Protocol,
    mockWebServer: MockWebServer,
  ) {
    setUp(protocol, mockWebServer)
    server.enqueue(
      MockResponse.Builder()
        .addHeaderLenient("Alpha", "α")
        .addHeaderLenient("β", "Beta")
        .build(),
    )
    val call = client.newCall(Request(server.url("/")))
    val response = call.execute()
    response.close()

    mockResponse = mockResponse.clearHeaders()
    mockResponse = mockResponse.addHeader("")
    mockResponse = mockResponse.addHeader("", "")
    mockResponse = mockResponse.addHeaderLenient("", Any())
    mockResponse = mockResponse.setHeader("", Any())
    mockResponse.headers = headersOf()
    mockResponse.trailers = headersOf()
    mockResponse = mockResponse.removeHeader("")