# frozen_string_literal: true

require "helper"

RSpec.describe HTTP2::Stream do
  include FrameHelpers
  let(:f) { Framer.new }
  let(:client) { Client.new }
  let(:stream) { client.new_stream }

  context "stream states" do
    it "should initiliaze all streams to IDLE" do
      expect(stream.state).to eq :idle
    end

    it "should set custom stream priority" do
      stream = client.new_stream(weight: 3, dependency: 2, exclusive: true)
      expect(stream.weight).to eq 3
    end

    context "idle" do
      it "should transition to open on sent HEADERS" do
        stream.send headers_frame
        expect(stream.state).to eq :open
      end
      it "should transition to open on received HEADERS" do
        stream.receive headers_frame
        expect(stream.state).to eq :open
      end
      it "should transition to reserved (local) on sent PUSH_PROMISE" do
        stream.send push_promise_frame
        expect(stream.state).to eq :reserved_local
      end
      it "should transition to reserved (remote) on received PUSH_PROMISE" do
        stream.receive push_promise_frame
        expect(stream.state).to eq :reserved_remote
      end
      it "should reprioritize stream on sent PRIORITY" do
        expect { stream.send priority_frame }.to_not raise_error
        expect(stream.weight).to eq 20
      end
      it "should reprioritize stream on received PRIORITY" do
        expect { stream.send priority_frame }.to_not raise_error
        expect(stream.weight).to eq 20
      end
    end

    context "reserved (local)" do
      before { stream.send push_promise_frame }

      it "should transition on sent PUSH_PROMISE" do
        expect(stream.state).to eq :reserved_local
      end

      it "should allow HEADERS to be sent" do
        expect { stream.send headers_frame }.to_not raise_error
      end

      it "should raise error if sending invalid frames" do
        frame_types.reject { |frame| %i[headers rst_stream priority].include?(frame[:type]) }.each do |type|
          expect { stream.dup.send type }.to raise_error InternalError
        end
      end

      it "should raise error on receipt of invalid frames" do
        what_types = frame_types.reject { |frame| %i[priority window_update rst_stream].include?(frame[:type]) }
        what_types.each do |type|
          expect { stream.dup.receive type }.to raise_error InternalError
        end
      end

      it "should transition to half closed (remote) on sent HEADERS" do
        stream.send headers_frame
        expect(stream.state).to eq :half_closed_remote
      end

      it "should transition to closed on sent RST_STREAM" do
        stream.close
        expect(stream.state).to eq :closed
      end

      it "should transition to closed on received RST_STREAM" do
        stream.receive rst_stream_frame
        expect(stream.state).to eq :closed
      end

      it "should reprioritize stream on PRIORITY" do
        expect { stream.receive priority_frame }.to_not raise_error
        expect(stream.weight).to eq 20
      end

      it "should increment remote_window on received WINDOW_UPDATE" do
        expect { stream.receive window_update_frame }.to_not raise_error
        expect(stream.remote_window).to eq DEFAULT_FLOW_WINDOW + window_update_frame[:increment]
      end

      it "should not increment connection remote_window on received WINDOW_UPDATE" do
        expect { stream.receive window_update_frame }.to_not raise_error
        expect(client.remote_window).to eq DEFAULT_FLOW_WINDOW
      end
    end

    context "reserved (remote)" do
      before { stream.receive push_promise_frame }

      it "should transition on received PUSH_PROMISE" do
        expect(stream.state).to eq :reserved_remote
      end

      it "should raise error if sending invalid frames" do
        frame_types.reject { |frame| %i[priority rst_stream window_update].include?(frame[:type]) }.each do |type|
          expect { stream.dup.send type }.to raise_error InternalError
        end
      end

      it "should raise error on receipt of invalid frames" do
        frame_types.reject { |frame| %i[headers rst_stream priority].include?(frame[:type]) }.each do |type|
          expect { stream.dup.receive type }.to raise_error InternalError
        end
      end

      it "should transition to half closed (local) on received HEADERS" do
        stream.receive headers_frame
        expect(stream.state).to eq :half_closed_local
      end

      it "should transition to closed on sent RST_STREAM" do
        stream.close
        expect(stream.state).to eq :closed
      end

      it "should transition to closed on received RST_STREAM" do
        stream.receive rst_stream_frame
        expect(stream.state).to eq :closed
      end

      it "should reprioritize stream on PRIORITY" do
        expect { stream.send priority_frame }.to_not raise_error
        expect(stream.weight).to eq 20
      end

      it "should increment local_window on sent WINDOW_UPDATE" do
        expect { stream.send window_update_frame }.to_not raise_error
        expect(stream.local_window).to eq DEFAULT_FLOW_WINDOW + window_update_frame[:increment]
      end
    end

    context "open" do
      before { stream.receive headers_frame }

      it "should allow any valid frames types to be sent" do
        (frame_types - [ping_frame, goaway_frame, settings_frame]).each do |type|
          expect { stream.dup.send type }.to_not raise_error
        end
      end

      it "should allow frames of any type to be received" do
        frame_types.each do |type|
          expect { stream.dup.receive type }.to_not raise_error
        end
      end

      it "should transition to half closed (local) if sending END_STREAM" do
        [data_frame, headers_frame].each do |frame|
          s = stream.dup

          s.send frame.merge(flags: [:end_stream])
          expect(s.state).to eq :half_closed_local
        end
      end

      it "should transition to half closed (remote) if receiving END_STREAM" do
        [data_frame, headers_frame].each do |frame|
          s = stream.dup
          f = frame.dup
          f[:flags] = [:end_stream]

          s.receive f
          expect(s.state).to eq :half_closed_remote
        end
      end

      it "should transition to half closed if remote opened with END_STREAM" do
        s = client.new_stream
        hclose = headers_frame
        hclose[:flags] = [:end_stream]

        s.receive hclose
        expect(s.state).to eq :half_closed_remote
      end

      it "should transition to half closed if local opened with END_STREAM" do
        s = client.new_stream
        hclose = headers_frame
        hclose[:flags] = [:end_stream]

        s.send hclose
        expect(s.state).to eq :half_closed_local
      end

      it "should transition to closed if sending RST_STREAM" do
        stream.close
        expect(stream.state).to eq :closed
        expect(stream).to be_closed
      end

      it "should transition to closed if receiving RST_STREAM" do
        stream.receive rst_stream_frame
        expect(stream.state).to eq :closed
      end

      it "should emit :active on open transition" do
        openp = false
        openr = false
        sp = client.new_stream
        sr = client.new_stream
        sp.on(:active) { openp = true }
        sr.on(:active) { openr = true }

        sp.receive headers_frame
        sr.send headers_frame

        expect(openp).to be_truthy
        expect(openr).to be_truthy
      end

      it "should not emit :active on transition from open" do
        order = []
        stream = client.new_stream

        stream.on(:active) { order << :active }
        stream.on(:half_close) { order << :half_close }
        stream.on(:close) { order << :close }

        req = headers_frame
        req[:flags] = [:end_headers]

        stream.send req
        stream.send data_frame
        expect(order).to eq %i[active half_close]
      end

      it "should emit :close on close transition" do
        closep = false
        closer = false
        sp = stream.dup
        sr = stream.dup

        sp.on(:close) { closep = true }
        sr.on(:close) { closer = true }

        sp.receive rst_stream_frame
        sr.close

        expect(closep).to be_truthy
        expect(closer).to be_truthy
      end

      it "should emit :close after frame is processed" do
        order = []
        stream = client.new_stream

        stream.on(:active) { order << :active }
        stream.on(:data)   { order << :data }
        stream.on(:half_close) { order << :half_close }
        stream.on(:close) { order << :close }

        req = headers_frame
        req[:flags] = %i[end_stream end_headers]

        stream.send req
        stream.receive headers_frame
        stream.receive data_frame

        expect(order).to eq %i[active half_close data close]
      end

      it "should emit :close with reason" do
        reason = nil
        stream.on(:close) { |r| reason = r }
        stream.receive rst_stream_frame
        expect(reason).not_to be_nil
      end

      it "should reprioritize stream on sent PRIORITY" do
        expect { stream.send priority_frame }.to_not raise_error
        expect(stream.weight).to eq 20
      end
      it "should reprioritize stream on received PRIORITY" do
        expect { stream.receive priority_frame }.to_not raise_error
        expect(stream.weight).to eq 20
      end
    end

    context "half closed (local)" do
      before { stream.send headers_frame.merge(flags: %i[end_headers end_stream]) }

      it "should raise error on attempt to send invalid frames" do
        frame_types.reject { |frame| %i[priority rst_stream window_update].include?(frame[:type]) }.each do |frame|
          expect { stream.dup.send frame }.to raise_error InternalError
        end
      end

      it "should transition to closed on receipt of END_STREAM flag" do
        [data_frame, headers_frame, continuation_frame].each do |frame|
          s = stream.dup
          f = frame.dup
          f[:flags] = [:end_stream]

          s.receive f
          expect(s.state).to eq :closed
        end
      end

      it "should transition to closed on receipt of RST_STREAM frame" do
        stream.receive rst_stream_frame
        expect(stream.state).to eq :closed
      end

      it "should transition to closed if RST_STREAM frame is sent" do
        stream.send rst_stream_frame
        expect(stream.state).to eq :closed
      end

      it "should ignore received WINDOW_UPDATE frames" do
        expect { stream.receive window_update_frame }.to_not raise_error
        expect(stream.state).to eq :half_closed_local
      end

      it "should ignore received PRIORITY frames" do
        expect { stream.receive priority_frame }.to_not raise_error
        expect(stream.state).to eq :half_closed_local
      end

      it "should reprioritize stream on sent PRIORITY" do
        expect { stream.send priority_frame }.to_not raise_error
        expect(stream.weight).to eq 20
      end

      it "should reprioritize stream (and decendants) on received PRIORITY" do
        expect { stream.receive priority_frame }.to_not raise_error
        expect(stream.weight).to eq 20
      end

      it "should increment local_window on sent WINDOW_UPDATE" do
        expect { stream.send window_update_frame }.to_not raise_error
        expect(stream.local_window).to eq DEFAULT_FLOW_WINDOW + window_update_frame[:increment]
      end

      it "should emit :half_close event on transition" do
        order = []
        stream = client.new_stream
        stream.on(:active) { order << :active }
        stream.on(:half_close) { order << :half_close }

        req = headers_frame
        req[:flags] = %i[end_stream end_headers]

        stream.send req
        expect(order).to eq %i[active half_close]
      end

      it "should emit :close event on transition to closed" do
        closed = false
        stream.on(:close) { closed = true }
        stream.receive rst_stream_frame

        expect(stream.state).to eq :closed
        expect(closed).to be_truthy
      end
    end

    context "half closed (remote)" do
      before { stream.receive headers_frame.merge(flags: %i[end_headers end_stream]) }

      it "should raise STREAM_CLOSED error on reciept of frames" do
        (frame_types - [priority_frame, rst_stream_frame, window_update_frame]).each do |frame|
          expect do
            stream.dup.receive frame
          end.to raise_error(StreamClosed)
        end
      end

      it "should transition to closed if END_STREAM flag is sent" do
        [data_frame, headers_frame].each do |frame|
          s = stream.dup

          s.on(:close) { expect(s.state).to eq :closed }
          s.send frame.merge(flags: [:end_stream])
          expect(s.state).to eq :closed
        end
      end

      it "should not transition to closed if END_STREAM flag is sent when overflowing window" do
        stream.on(:close) { raise "should not have closed" }
        data = { type: :data, flags: [], stream: stream.id }
        4.times do
          data = data.merge(flags: [:end_stream]) if stream.remote_window < 16_384
          stream.send data.merge(payload: "x" * 16_384)
        end
      end

      it "should transition to closed when send buffer is emptied" do
        o = Object.new
        expect(o).to receive(:tap).once
        stream.on(:close) do
          expect(stream.buffered_amount).to eq 0
          o.tap
        end
        data = { type: :data, flags: [], stream: stream.id }
        4.times do
          data = data.merge(flags: [:end_stream]) if stream.remote_window < 16_384
          stream.send data.merge(payload: "x" * 16_384)
        end
        client << f.generate(settings_frame)
        client << Framer.new.generate(type: :window_update, stream: stream.id, increment: 16_384)
      end

      it "should transition to closed if RST_STREAM is sent" do
        stream.close
        expect(stream.state).to eq :closed
      end

      it "should transition to closed on reciept of RST_STREAM frame" do
        stream.receive rst_stream_frame
        expect(stream.state).to eq :closed
      end

      it "should ignore sent WINDOW_UPDATE frames" do
        expect { stream.send window_update_frame }.to_not raise_error
        expect(stream.state).to eq :half_closed_remote
      end

      it "should increment remote_window on received WINDOW_UPDATE" do
        expect { stream.receive window_update_frame }.to_not raise_error
        expect(stream.remote_window).to eq DEFAULT_FLOW_WINDOW + window_update_frame[:increment]
      end

      it "should reprioritize stream on sent PRIORITY" do
        expect { stream.send priority_frame }.to_not raise_error
        expect(stream.weight).to eq 20
      end
      it "should reprioritize stream on received PRIORITY" do
        expect { stream.receive priority_frame }.to_not raise_error
        expect(stream.weight).to eq 20
      end

      it "should emit :half_close event on transition" do
        order = []
        stream = client.new_stream
        stream.on(:active) { order << :active }
        stream.on(:half_close) { order << :half_close }

        req = headers_frame
        req[:flags] = %i[end_stream end_headers]

        stream.receive req
        expect(order).to eq %i[active half_close]
      end

      it "should emit :close event on close transition" do
        closed = false
        stream.on(:close) { closed = true }
        stream.close

        expect(stream.state).to eq :closed
        expect(closed).to be_truthy
      end
    end

    context "closed" do
      context "remote closed stream" do
        before do
          stream.send headers_frame.merge(flags: %i[end_headers end_stream])     # half closed local
          stream.receive headers_frame.merge(flags: %i[end_headers end_stream])  # closed by remote
        end

        it "should raise STREAM_CLOSED on attempt to send frames" do
          (frame_types - [priority_frame, rst_stream_frame]).each do |frame|
            expect do
              stream.dup.send frame
            end.to raise_error(StreamClosed)
          end
        end

        it "should raise STREAM_CLOSED on receipt of frame" do
          (frame_types - [priority_frame, rst_stream_frame, window_update_frame]).each do |frame|
            expect do
              stream.dup.receive frame
            end.to raise_error(StreamClosed)
          end
        end

        it "should allow PRIORITY, RST_STREAM to be sent" do
          expect { stream.send priority_frame }.to_not raise_error
          expect { stream.send rst_stream_frame }.to_not raise_error
        end

        it "should allow PRIORITY, RST_STREAM to be received" do
          expect { stream.receive priority_frame }.to_not raise_error
          expect { stream.receive rst_stream_frame }.to_not raise_error
        end

        it "should reprioritize stream on sent PRIORITY" do
          expect { stream.send priority_frame }.to_not raise_error
          expect(stream.weight).to eq 20
        end
        it "should reprioritize stream on received PRIORITY" do
          expect { stream.receive priority_frame }.to_not raise_error
          expect(stream.weight).to eq 20
        end

        it "should ignore received WINDOW_UPDATE frames" do
          expect { stream.receive window_update_frame }.to_not raise_error
          expect(stream.state).to eq :closed
        end
      end

      context "local closed via RST_STREAM frame" do
        before do
          stream.send headers_frame     # open
          stream.send rst_stream_frame  # closed by local
        end

        it "should ignore received frames" do
          control_frames.each do |frame|
            expect do
              cb = []
              stream.on(:data) { cb << :data }
              stream.on(:headers) { cb << :headers }
              stream.dup.receive frame
              expect(cb).to be_empty
            end.to_not raise_error
          end
        end

        # it "should transition to reserved remote on PUSH_PROMISE" do
        # An endpoint might receive a PUSH_PROMISE frame after it sends
        # RST_STREAM.  PUSH_PROMISE causes a stream to become "reserved".
        # ...
        # We're auto RST'ing PUSH streams in connection class, hence
        # skipping this transition for now.
        # end
      end

      # FIXME: Isn't this test same as "half closed (local)"?
      # context "local closed via END_STREAM flag" do
      #   before(:each) do
      #     stream.send headers_frame  # open
      #     stream.send data_frame     # contains end_stream flag
      #   end

      #   it "should ignore received frames" do
      #     frame_types.each do |frame|
      #       expect { stream.dup.receive frame }.to_not raise_error
      #     end
      #   end
      # end
    end
  end

  # TODO: add test cases to ensure on(:priority) emitted after close

  context "flow control" do
    it "should initialize to default flow control window" do
      expect(stream.remote_window).to eq DEFAULT_FLOW_WINDOW
    end

    it "should update window size on DATA frames only" do
      stream.send headers_frame # go to open
      expect(stream.remote_window).to eq DEFAULT_FLOW_WINDOW

      (frame_types - [data_frame, ping_frame, goaway_frame, settings_frame]).each do |frame|
        s = stream.dup
        s.send frame
        expect(s.remote_window).to eq DEFAULT_FLOW_WINDOW
      end

      stream.send data_frame
      expect(stream.remote_window).to eq DEFAULT_FLOW_WINDOW - data_frame[:payload].bytesize
    end

    it "should update window size on receipt of WINDOW_UPDATE" do
      stream.send headers_frame
      stream.send data_frame
      stream.receive window_update_frame

      expect(stream.remote_window).to eq(
        DEFAULT_FLOW_WINDOW - data_frame[:payload].bytesize + window_update_frame[:increment]
      )
    end

    it "should observe session flow control" do
      settings = settings_frame
      data = data_frame
      settings[:payload] = [[:settings_initial_window_size, 1000]]
      settings[:stream] = 0

      framer = Framer.new
      client << framer.generate(settings)

      s1 = client.new_stream
      s1.send headers_frame
      s1.send data.merge(payload: "x" * 900, flags: [])
      expect(s1.remote_window).to eq 100

      s1.send data.merge(payload: "x" * 200)
      expect(s1.remote_window).to eq 0
      expect(s1.buffered_amount).to eq 100

      client << framer.generate(window_update_frame.merge(stream: s1.id, increment: 1000))
      expect(s1.buffered_amount).to eq 0
      expect(s1.remote_window).to eq 900
    end

    it "should not update window when data received is less than half of maximum local window size" do
      data = data_frame
      datalen = data[:payload].bytesize
      expect(stream).not_to receive(:send) do |frame|
        expect(frame[:type]).to eq :window_update
        expect(frame[:increment]).to eq datalen
      end
      stream.receive headers_frame
      stream.receive data
    end

    it "should update window when data received is over half of the maximum local window size" do
      data1 = data_frame.merge(payload: "a" * 16_384, flags: [])
      data2 = data_frame.merge(payload: "a" * 16_384)
      datalen = 16_384 * 2
      expect(stream).to receive(:send) do |frame|
        expect(frame[:type]).to eq :window_update
        expect(frame[:increment]).to eq datalen
      end
      stream.receive headers_frame
      stream.receive data1
      stream.receive data2
    end

    it "should send a DATA frame with size 0 when there is no window, as long as end_stream flag is set" do
      settings = settings_frame
      data = data_frame
      settings[:payload] = [[:settings_initial_window_size, 1000]]
      settings[:stream] = 0

      framer = Framer.new
      client << framer.generate(settings)

      s1 = client.new_stream
      s1.send headers_frame
      s1.send data.merge(payload: "x" * 1000, flags: [])

      # check if window is exhausted
      expect(s1.remote_window).to be(0)
      expect(s1.send_buffer).to be_empty

      s1.send data.merge(payload: "", flags: [:end_stream])

      expect(s1.remote_window).to be(0)
      expect(s1.send_buffer).to be_empty
    end
  end

  context "client API" do
    it ".reprioritize should emit PRIORITY frame" do
      expect(stream).to receive(:send) do |frame|
        expect(frame[:type]).to eq :priority
        expect(frame[:weight]).to eq 30
      end

      stream.reprioritize weight: 30
    end

    it ".reprioritize should raise error if invoked by server" do
      srv = Server.new
      stream = srv.new_stream

      expect { stream.reprioritize(weight: 10) }.to raise_error(InternalError)
    end

    it ".headers should emit HEADERS frames" do
      payload = {
        ":method" => "GET",
        ":scheme" => "http",
        ":host" => "www.example.org",
        ":path" => "/resource",
        "custom" => "value"
      }

      expect(stream).to receive(:send) do |frame|
        expect(frame[:type]).to eq :headers
        expect(frame[:payload]).to eq payload
        expect(frame[:flags]).to eq [:end_headers]
      end

      stream.headers(payload, end_stream: false, end_headers: true)
    end

    it ".data should emit DATA frames" do
      expect(stream).to receive(:send) do |frame|
        expect(frame[:type]).to eq :data
        expect(frame[:payload]).to eq "text"
        expect(frame[:flags]).to be_empty
      end
      stream.data("text", end_stream: false)

      expect(stream).to receive(:send) do |frame|
        expect(frame[:flags]).to eq [:end_stream]
      end
      stream.data("text")
    end

    it ".data should split large DATA frames" do
      data = "x" * 16_384 * 2

      want = [
        { type: :data, flags: [], length: 16_384 },
        { type: :data, flags: [], length: 16_384 },
        { type: :data, flags: [:end_stream], length: 1 }
      ]
      want.each do |w|
        expect(stream).to receive(:send) do |frame|
          expect(frame[:type]).to eq w[:type]
          expect(frame[:flags]).to eq w[:flags]
          expect(frame[:payload].bytesize).to eq w[:length]
        end
      end

      stream.data("#{data}x")
    end

    it ".data should split large multibyte DATA frames" do
      data = "🐼" * 16_384

      want = [
        { type: :data, flags: [], length: 16_384 },
        { type: :data, flags: [], length: 16_384 },
        { type: :data, flags: [], length: 16_384 },
        { type: :data, flags: [], length: 16_384 },
        { type: :data, flags: [:end_stream], length: 1 }
      ]
      want.each do |w|
        expect(stream).to receive(:send) do |frame|
          expect(frame[:type]).to eq w[:type]
          expect(frame[:flags]).to eq w[:flags]
          expect(frame[:payload].bytesize).to eq w[:length]
        end
      end

      stream.data("#{data}x")
    end

    it ".cancel should reset stream with cancel error code" do
      expect(stream).to receive(:send) do |frame|
        expect(frame[:type]).to eq :rst_stream
        expect(frame[:error]).to eq :cancel
      end

      stream.cancel
    end

    it ".refuse should reset stream with refused stream error code" do
      expect(stream).to receive(:send) do |frame|
        expect(frame[:type]).to eq :rst_stream
        expect(frame[:error]).to eq :refused_stream
      end

      stream.refuse
    end

    it ".window_update should emit WINDOW_UPDATE frames" do
      expect(stream).to receive(:send) do |frame|
        expect(frame[:type]).to eq :window_update
        expect(frame[:increment]).to eq 20
      end
      stream.window_update(20)
    end
  end

  context "server API" do
    let(:srv) { Server.new }
    let(:frm) { Framer.new }
    let(:client_stream) { client.new_stream }
    before do
      client.on(:frame) { |bytes| srv << bytes }
    end

    it "should emit received headers via on(:headers)" do
      headers = REQUEST_HEADERS
      recv = nil
      srv.on(:stream) do |stream|
        stream.on(:headers) { |h| recv = h }
      end

      client_stream.headers(headers)
      expect(recv).to eq headers
    end

    it "should emit received payload via on(:data)" do
      payload = "some-payload"
      srv.on(:stream) do |stream|
        stream.on(:data) do |recv|
          expect(recv).to eq payload
        end
      end

      client_stream.headers(REQUEST_HEADERS)
      client_stream.data(payload)
    end

    it "should emit received priority parameters via on(:priority)" do
      new_weight = 15
      new_dependency = client_stream.id + 2
      callback_called = false
      srv.on(:stream) do |stream|
        stream.on(:priority) do |pri|
          callback_called = true
          expect(pri.is_a?(Hash)).to be
          expect(pri[:weight]).to eq new_weight
          expect(pri[:dependency]).to eq new_dependency
        end
      end

      client_stream.headers(REQUEST_HEADERS)
      client_stream.reprioritize(weight: new_weight, dependency: new_dependency)
      expect(callback_called).to be
    end

    context "push" do
      before(:each) do
        srv.on(:frame)  { |bytes| client << bytes }
        srv.on(:stream) do |stream|
          @server_stream = stream
        end

        client_stream.headers(REQUEST_HEADERS)
      end

      it ".promise should emit server initiated stream" do
        push = nil
        @server_stream.promise(REQUEST_HEADERS) { |pstream| push = pstream }
        expect(push.id).to eq 2
      end

      it ".promise push stream should have parent stream" do
        push = nil
        @server_stream.promise(REQUEST_HEADERS) { |pstream| push = pstream }

        expect(push.state).to eq :reserved_local
        expect(push.parent.id).to eq @server_stream.id
      end

      context "stream states" do
        it "server: active > half close > close" do
          order = []
          @server_stream.promise(REQUEST_HEADERS) do |push|
            stream = push

            expect(push.state).to eq :reserved_local
            order << :reserved

            push.on(:active) { order << :active }
            push.on(:half_close) { order << :half_close }
            push.on(:close) { order << :close }

            push.headers(RESPONSE_HEADERS)
            push.send data_frame.merge(stream: stream.id)
          end

          expect(order).to eq %i[reserved active half_close close]
        end

        it "client: promise_headers > active > headers > .. > data > close" do
          order = []
          headers = []
          promise_headers = []
          client.on(:promise) do |push|
            order << :reserved

            push.on(:active)    { order << :active }
            push.on(:data)      { order << :data }
            push.on(:half_close) { order << :half_close }
            push.on(:close) { order << :close }

            push.on(:promise_headers) do |h|
              order << :promise_headers
              promise_headers += h
            end
            push.on(:headers) do |h|
              order << :headers
              headers += h
            end

            expect(push.id).to be_even
          end

          @server_stream.promise(REQUEST_HEADERS) do |push|
            push.headers(RESPONSE_HEADERS)
            push.data("somedata")
          end

          expect(promise_headers).to eq(REQUEST_HEADERS)
          expect(headers).to eq(RESPONSE_HEADERS)
          expect(order).to eq %i[
            reserved
            promise_headers
            active
            headers
            half_close
            data
            close
          ]
        end
      end
    end
  end
end