text: """Test the stream worker corner cases.
  
  Exercise the stream worker functionality by mocking av.open calls to return a
  fake media container as well a fake decoded stream in the form of a series of
  packets. This is needed as some of these cases can't be encoded using pyav.  It
  is preferred to use test_hls.py for example, when possible.
  
  The worker opens the stream source (typically a URL) and gets back a
  container that has audio/video streams. The worker iterates over the sequence
  of packets and sends them to the appropriate output buffers. Each test
  creates a packet sequence, with a mocked output buffer to capture the segments
  pushed to the output streams. The packet sequence can be used to exercise
  failure modes or corner cases like how out of order packets are handled.
  """
  
  import fractions
  import io
  import math
  import threading
  from unittest.mock import patch
  
  import av
  
  from homeassistant.components.stream import Stream
  from homeassistant.components.stream.const import (
      MAX_MISSING_DTS,
      MIN_SEGMENT_DURATION,
      PACKETS_TO_WAIT_FOR_AUDIO,
  )
  from homeassistant.components.stream.worker import SegmentBuffer, stream_worker
  
  STREAM_SOURCE = "some-stream-source"
  # Formats here are arbitrary, not exercised by tests
  STREAM_OUTPUT_FORMAT = "hls"
  AUDIO_STREAM_FORMAT = "mp3"
  VIDEO_STREAM_FORMAT = "h264"
  VIDEO_FRAME_RATE = 12
  AUDIO_SAMPLE_RATE = 11025
  PACKET_DURATION = fractions.Fraction(1, VIDEO_FRAME_RATE)  # in seconds
  SEGMENT_DURATION = (
      math.ceil(MIN_SEGMENT_DURATION / PACKET_DURATION) * PACKET_DURATION
  )  # in seconds
  TEST_SEQUENCE_LENGTH = 5 * VIDEO_FRAME_RATE
  LONGER_TEST_SEQUENCE_LENGTH = 20 * VIDEO_FRAME_RATE
  OUT_OF_ORDER_PACKET_INDEX = 3 * VIDEO_FRAME_RATE
  PACKETS_PER_SEGMENT = SEGMENT_DURATION / PACKET_DURATION
  SEGMENTS_PER_PACKET = PACKET_DURATION / SEGMENT_DURATION
  TIMEOUT = 15
  
  
  class FakePyAvStream:
      """A fake pyav Stream."""
  
      def __init__(self, name, rate):
          """Initialize the stream."""
          self.name = name
          self.time_base = fractions.Fraction(1, rate)
          self.profile = "ignored-profile"
  
  
  VIDEO_STREAM = FakePyAvStream(VIDEO_STREAM_FORMAT, VIDEO_FRAME_RATE)
  AUDIO_STREAM = FakePyAvStream(AUDIO_STREAM_FORMAT, AUDIO_SAMPLE_RATE)
  
  
  class PacketSequence:
      """Creates packets in a sequence for exercising stream worker behavior.
  
      A test can create a PacketSequence(N) that will raise a StopIteration after
      N packets.  Each packet has an arbitrary monotomically increasing dts/pts value
      that is parseable by the worker, but a test can manipulate the values to
      exercise corner cases.
      """
  
      def __init__(self, num_packets):
          """Initialize the sequence with the number of packets it provides."""
          self.packet = 0
          self.num_packets = num_packets
  
      def __iter__(self):
          """Reset the sequence."""
          self.packet = 0
          return self
  
      def __next__(self):
          """Return the next packet."""
          if self.packet >= self.num_packets:
              raise StopIteration
          self.packet += 1
  
          class FakePacket:
              time_base = fractions.Fraction(1, VIDEO_FRAME_RATE)
              dts = self.packet * PACKET_DURATION / time_base
              pts = self.packet * PACKET_DURATION / time_base
              duration = PACKET_DURATION / time_base
              stream = VIDEO_STREAM
              is_keyframe = True
  
          return FakePacket()
  
  
  class FakePyAvContainer:
      """A fake container returned by mock av.open for a stream."""
  
      def __init__(self, video_stream, audio_stream):
          """Initialize the fake container."""
          # Tests can override this to trigger different worker behavior
          self.packets = PacketSequence(0)
  
          class FakePyAvStreams:
              video = video_stream
              audio = audio_stream
  
          self.streams = FakePyAvStreams()
  
          class FakePyAvFormat:
              name = "ignored-format"
  
          self.format = FakePyAvFormat()
  
      def demux(self, streams):
          """Decode the streams from container, and return a packet sequence."""
          return self.packets
  
      def close(self):
          """Close the container."""
          return
  
  
  class FakePyAvBuffer:
      """Holds outputs of the decoded stream for tests to assert on results."""
  
      def __init__(self):
          """Initialize the FakePyAvBuffer."""
          self.segments = []
          self.audio_packets = []
          self.video_packets = []
  
      def add_stream(self, template=None):
          """Create an output buffer that captures packets for test to examine."""
  
          class FakeStream:
              def __init__(self, capture_packets):
                  self.capture_packets = capture_packets
  
              def close(self):
                  return
  
              def mux(self, packet):
                  self.capture_packets.append(packet)
  
          if template.name == AUDIO_STREAM_FORMAT:
              return FakeStream(self.audio_packets)
          return FakeStream(self.video_packets)
  
      def mux(self, packet):
          """Capture a packet for tests to examine."""
          # Forward to appropriate FakeStream
          packet.stream.mux(packet)
  
      def close(self):
          """Close the buffer."""
          return
  
      def capture_output_segment(self, segment):
          """Capture the output segment for tests to inspect."""
          self.segments.append(segment)
  
  
  class MockPyAv:
      """Mocks out av.open."""
  
      def __init__(self, video=True, audio=False):
          """Initialize the MockPyAv."""
          video_stream = [VIDEO_STREAM] if video else []
          audio_stream = [AUDIO_STREAM] if audio else []
          self.container = FakePyAvContainer(
              video_stream=video_stream, audio_stream=audio_stream
          )
          self.capture_buffer = FakePyAvBuffer()
  
      def open(self, stream_source, *args, **kwargs):
          """Return a stream or buffer depending on args."""
          if isinstance(stream_source, io.BytesIO):
              return self.capture_buffer
          return self.container
  
  
  async def async_decode_stream(hass, packets, py_av=None):
      """Start a stream worker that decodes incoming stream packets into output segments."""
      stream = Stream(hass, STREAM_SOURCE)
      stream.add_provider(STREAM_OUTPUT_FORMAT)
  
      if not py_av:
          py_av = MockPyAv()
      py_av.container.packets = packets
  
      with patch("av.open", new=py_av.open), patch(
          "homeassistant.components.stream.core.StreamOutput.put",
          side_effect=py_av.capture_buffer.capture_output_segment,
      ):
          segment_buffer = SegmentBuffer(stream.outputs)
          stream_worker(STREAM_SOURCE, {}, segment_buffer, threading.Event())
          await hass.async_block_till_done()
  
      return py_av.capture_buffer
  
  
  async def test_stream_open_fails(hass):
      """Test failure on stream open."""
      stream = Stream(hass, STREAM_SOURCE)
      stream.add_provider(STREAM_OUTPUT_FORMAT)
      with patch("av.open") as av_open:
          av_open.side_effect = av.error.InvalidDataError(-2, "error")
          segment_buffer = SegmentBuffer(stream.outputs)
          stream_worker(STREAM_SOURCE, {}, segment_buffer, threading.Event())
          await hass.async_block_till_done()
          av_open.assert_called_once()
  
  
  async def test_stream_worker_success(hass):
      """Test a short stream that ends and outputs everything correctly."""
      decoded_stream = await async_decode_stream(
          hass, PacketSequence(TEST_SEQUENCE_LENGTH)
      )
      segments = decoded_stream.segments
      # Check number of segments. A segment is only formed when a packet from the next
      # segment arrives, hence the subtraction of one from the sequence length.
      assert len(segments) == int((TEST_SEQUENCE_LENGTH - 1) * SEGMENTS_PER_PACKET)
      # Check sequence numbers
      assert all([segments[i].sequence == i + 1 for i in range(len(segments))])
      # Check segment durations
      assert all([s.duration == SEGMENT_DURATION for s in segments])
      assert len(decoded_stream.video_packets) == TEST_SEQUENCE_LENGTH
      assert len(decoded_stream.audio_packets) == 0
  
  
  async def test_skip_out_of_order_packet(hass):
      """Skip a single out of order packet."""
      packets = list(PacketSequence(TEST_SEQUENCE_LENGTH))
      # This packet is out of order
      packets[OUT_OF_ORDER_PACKET_INDEX].dts = -9090
  
      decoded_stream = await async_decode_stream(hass, iter(packets))
      segments = decoded_stream.segments
      # Check sequence numbers
      assert all([segments[i].sequence == i + 1 for i in range(len(segments))])
      # If skipped packet would have been the first packet of a segment, the previous
      # segment will be longer by a packet duration
      # We also may possibly lose a segment due to the shifting pts boundary
      if OUT_OF_ORDER_PACKET_INDEX % PACKETS_PER_SEGMENT == 0:
          # Check duration of affected segment and remove it
          longer_segment_index = int(
              (OUT_OF_ORDER_PACKET_INDEX - 1) * SEGMENTS_PER_PACKET
          )
          assert (
              segments[longer_segment_index].duration
              == SEGMENT_DURATION + PACKET_DURATION
          )
          del segments[longer_segment_index]
          # Check number of segments
          assert len(segments) == int((len(packets) - 1 - 1) * SEGMENTS_PER_PACKET - 1)
      else:  # Otherwise segment durations and number of segments are unaffected
          # Check number of segments
          assert len(segments) == int((len(packets) - 1) * SEGMENTS_PER_PACKET)
      # Check remaining segment durations
      assert all([s.duration == SEGMENT_DURATION for s in segments])
      assert len(decoded_stream.video_packets) == len(packets) - 1
      assert len(decoded_stream.audio_packets) == 0
  
  
  async def test_discard_old_packets(hass):
      """Skip a series of out of order packets."""
  
      packets = list(PacketSequence(TEST_SEQUENCE_LENGTH))
      # Packets after this one are considered out of order
      packets[OUT_OF_ORDER_PACKET_INDEX - 1].dts = 9090
  
      decoded_stream = await async_decode_stream(hass, iter(packets))
      segments = decoded_stream.segments
      # Check number of segments
      assert len(segments) == int((OUT_OF_ORDER_PACKET_INDEX - 1) * SEGMENTS_PER_PACKET)
      # Check sequence numbers
      assert all([segments[i].sequence == i + 1 for i in range(len(segments))])
      # Check segment durations
      assert all([s.duration == SEGMENT_DURATION for s in segments])
      assert len(decoded_stream.video_packets) == OUT_OF_ORDER_PACKET_INDEX
      assert len(decoded_stream.audio_packets) == 0
  
  
  async def test_packet_overflow(hass):
      """Packet is too far out of order, and looks like overflow, ending stream early."""
  
      packets = list(PacketSequence(TEST_SEQUENCE_LENGTH))
      # Packet is so far out of order, exceeds max gap and looks like overflow
      packets[OUT_OF_ORDER_PACKET_INDEX].dts = -9000000
  
      decoded_stream = await async_decode_stream(hass, iter(packets))
      segments = decoded_stream.segments
      # Check number of segments
      assert len(segments) == int((OUT_OF_ORDER_PACKET_INDEX - 1) * SEGMENTS_PER_PACKET)
      # Check sequence numbers
      assert all([segments[i].sequence == i + 1 for i in range(len(segments))])
      # Check segment durations
      assert all([s.duration == SEGMENT_DURATION for s in segments])
      assert len(decoded_stream.video_packets) == OUT_OF_ORDER_PACKET_INDEX
      assert len(decoded_stream.audio_packets) == 0
  
  
  async def test_skip_initial_bad_packets(hass):
      """Tests a small number of initial "bad" packets with missing dts."""
  
      num_packets = LONGER_TEST_SEQUENCE_LENGTH
      packets = list(PacketSequence(num_packets))
      num_bad_packets = MAX_MISSING_DTS - 1
      for i in range(0, num_bad_packets):
          packets[i].dts = None
  
      decoded_stream = await async_decode_stream(hass, iter(packets))
      segments = decoded_stream.segments
      # Check number of segments
      assert len(segments) == int(
          (num_packets - num_bad_packets - 1) * SEGMENTS_PER_PACKET
      )
      # Check sequence numbers
      assert all([segments[i].sequence == i + 1 for i in range(len(segments))])
      # Check segment durations
      assert all([s.duration == SEGMENT_DURATION for s in segments])
      assert len(decoded_stream.video_packets) == num_packets - num_bad_packets
      assert len(decoded_stream.audio_packets) == 0
  
  
  async def test_too_many_initial_bad_packets_fails(hass):
      """Test initial bad packets are too high, causing it to never start."""
  
      num_packets = LONGER_TEST_SEQUENCE_LENGTH
      packets = list(PacketSequence(num_packets))
      num_bad_packets = MAX_MISSING_DTS + 1
      for i in range(0, num_bad_packets):
          packets[i].dts = None
  
      decoded_stream = await async_decode_stream(hass, iter(packets))
      segments = decoded_stream.segments
      assert len(segments) == 0
      assert len(decoded_stream.video_packets) == 0
      assert len(decoded_stream.audio_packets) == 0
  
  
  async def test_skip_missing_dts(hass):
      """Test packets in the middle of the stream missing DTS are skipped."""
  
      num_packets = LONGER_TEST_SEQUENCE_LENGTH
      packets = list(PacketSequence(num_packets))
      bad_packet_start = int(LONGER_TEST_SEQUENCE_LENGTH / 2)
      num_bad_packets = MAX_MISSING_DTS - 1
      for i in range(bad_packet_start, bad_packet_start + num_bad_packets):
          packets[i].dts = None
  
      decoded_stream = await async_decode_stream(hass, iter(packets))
      segments = decoded_stream.segments
      # Check sequence numbers
      assert all([segments[i].sequence == i + 1 for i in range(len(segments))])
      # Check segment durations (not counting the elongated segment)
      assert (
          sum([segments[i].duration == SEGMENT_DURATION for i in range(len(segments))])
          >= len(segments) - 1
      )
      assert len(decoded_stream.video_packets) == num_packets - num_bad_packets
      assert len(decoded_stream.audio_packets) == 0
  
  
  async def test_too_many_bad_packets(hass):
      """Test bad packets are too many, causing it to end."""
  
      num_packets = LONGER_TEST_SEQUENCE_LENGTH
      packets = list(PacketSequence(num_packets))
      bad_packet_start = int(LONGER_TEST_SEQUENCE_LENGTH / 2)
      num_bad_packets = MAX_MISSING_DTS + 1
      for i in range(bad_packet_start, bad_packet_start + num_bad_packets):
          packets[i].dts = None
  
      decoded_stream = await async_decode_stream(hass, iter(packets))
      segments = decoded_stream.segments
      assert len(segments) == int((bad_packet_start - 1) * SEGMENTS_PER_PACKET)
      assert len(decoded_stream.video_packets) == bad_packet_start
      assert len(decoded_stream.audio_packets) == 0
  
  
  async def test_no_video_stream(hass):
      """Test no video stream in the container means no resulting output."""
      py_av = MockPyAv(video=False)
  
      decoded_stream = await async_decode_stream(
          hass, PacketSequence(TEST_SEQUENCE_LENGTH), py_av=py_av
      )
      # Note: This failure scenario does not output an end of stream
      segments = decoded_stream.segments
      assert len(segments) == 0
      assert len(decoded_stream.video_packets) == 0
      assert len(decoded_stream.audio_packets) == 0
  
  
  async def test_audio_packets_not_found(hass):
      """Set up an audio stream, but no audio packets are found."""
      py_av = MockPyAv(audio=True)
  
      num_packets = PACKETS_TO_WAIT_FOR_AUDIO + 1
      packets = PacketSequence(num_packets)  # Contains only video packets
  
      decoded_stream = await async_decode_stream(hass, iter(packets), py_av=py_av)
      segments = decoded_stream.segments
      assert len(segments) == int((num_packets - 1) * SEGMENTS_PER_PACKET)
      assert len(decoded_stream.video_packets) == num_packets
      assert len(decoded_stream.audio_packets) == 0
  
  
  async def test_audio_is_first_packet(hass):
      """Set up an audio stream and audio packet is the first packet in the stream."""
      py_av = MockPyAv(audio=True)
  
      num_packets = PACKETS_TO_WAIT_FOR_AUDIO + 1
      packets = list(PacketSequence(num_packets))
      # Pair up an audio packet for each video packet
      packets[0].stream = AUDIO_STREAM
      packets[0].dts = packets[1].dts / VIDEO_FRAME_RATE * AUDIO_SAMPLE_RATE
      packets[0].pts = packets[1].pts / VIDEO_FRAME_RATE * AUDIO_SAMPLE_RATE
      packets[2].stream = AUDIO_STREAM
      packets[2].dts = packets[3].dts / VIDEO_FRAME_RATE * AUDIO_SAMPLE_RATE
      packets[2].pts = packets[3].pts / VIDEO_FRAME_RATE * AUDIO_SAMPLE_RATE
  
      decoded_stream = await async_decode_stream(hass, iter(packets), py_av=py_av)
      segments = decoded_stream.segments
      # The audio packets are segmented with the video packets
      assert len(segments) == int((num_packets - 2 - 1) * SEGMENTS_PER_PACKET)
      assert len(decoded_stream.video_packets) == num_packets - 2
      assert len(decoded_stream.audio_packets) == 1
  
  
  async def test_audio_packets_found(hass):
      """Set up an audio stream and audio packets are found at the start of the stream."""
      py_av = MockPyAv(audio=True)
  
      num_packets = PACKETS_TO_WAIT_FOR_AUDIO + 1
      packets = list(PacketSequence(num_packets))
      packets[1].stream = AUDIO_STREAM
      packets[1].dts = packets[0].dts / VIDEO_FRAME_RATE * AUDIO_SAMPLE_RATE
      packets[1].pts = packets[0].pts / VIDEO_FRAME_RATE * AUDIO_SAMPLE_RATE
  
      decoded_stream = await async_decode_stream(hass, iter(packets), py_av=py_av)
      segments = decoded_stream.segments
      # The audio packet above is buffered with the video packet
      assert len(segments) == int((num_packets - 1 - 1) * SEGMENTS_PER_PACKET)
      assert len(decoded_stream.video_packets) == num_packets - 1
      assert len(decoded_stream.audio_packets) == 1
  
  
  async def test_pts_out_of_order(hass):
      """Test pts can be out of order and still be valid."""
  
      # Create a sequence of packets with some out of order pts
      packets = list(PacketSequence(TEST_SEQUENCE_LENGTH))
      for i, _ in enumerate(packets):
          if i % PACKETS_PER_SEGMENT == 1:
              packets[i].pts = packets[i - 1].pts - 1
              packets[i].is_keyframe = False
  
      decoded_stream = await async_decode_stream(hass, iter(packets))
      segments = decoded_stream.segments
      # Check number of segments
      assert len(segments) == int((TEST_SEQUENCE_LENGTH - 1) * SEGMENTS_PER_PACKET)
      # Check sequence numbers
      assert all([segments[i].sequence == i + 1 for i in range(len(segments))])
      # Check segment durations
      assert all([s.duration == SEGMENT_DURATION for s in segments])
      assert len(decoded_stream.video_packets) == len(packets)
      assert len(decoded_stream.audio_packets) == 0
  
  
  async def test_stream_stopped_while_decoding(hass):
      """Tests that worker quits when stop() is called while decodign."""
      # Add some synchronization so that the test can pause the background
      # worker. When the worker is stopped, the test invokes stop() which
      # will cause the worker thread to exit once it enters the decode
      # loop
      worker_open = threading.Event()
      worker_wake = threading.Event()
  
      stream = Stream(hass, STREAM_SOURCE)
      stream.add_provider(STREAM_OUTPUT_FORMAT)
  
      py_av = MockPyAv()
      py_av.container.packets = PacketSequence(TEST_SEQUENCE_LENGTH)
  
      def blocking_open(stream_source, *args, **kwargs):
          # Let test know the thread is running
          worker_open.set()
          # Block worker thread until test wakes up
          worker_wake.wait()
          return py_av.open(stream_source, args, kwargs)
  
      with patch("av.open", new=blocking_open):
          stream.start()
          assert worker_open.wait(TIMEOUT)
          # Note: There is a race here where the worker could start as soon
          # as the wake event is sent, completing all decode work.
          worker_wake.set()
          stream.stop()
  
  
  async def test_update_stream_source(hass):
      """Tests that the worker is re-invoked when the stream source is updated."""
      worker_open = threading.Event()
      worker_wake = threading.Event()
  
      stream = Stream(hass, STREAM_SOURCE)
      stream.add_provider(STREAM_OUTPUT_FORMAT)
      # Note that keepalive is not set here.  The stream is "restarted" even though
      # it is not stopping due to failure.
  
      py_av = MockPyAv()
      py_av.container.packets = PacketSequence(TEST_SEQUENCE_LENGTH)
  
      last_stream_source = None
  
      def blocking_open(stream_source, *args, **kwargs):
          nonlocal last_stream_source
          if not isinstance(stream_source, io.BytesIO):
              last_stream_source = stream_source
          # Let test know the thread is running
          worker_open.set()
          # Block worker thread until test wakes up
          worker_wake.wait()
          return py_av.open(stream_source, args, kwargs)
  
      with patch("av.open", new=blocking_open):
          stream.start()
          assert worker_open.wait(TIMEOUT)
          assert last_stream_source == STREAM_SOURCE
  
          # Update the stream source, then the test wakes up the worker and assert
          # that it re-opens the new stream (the test again waits on thread_started)
          worker_open.clear()
          stream.update_source(STREAM_SOURCE + "-updated-source")
          worker_wake.set()
          assert worker_open.wait(TIMEOUT)
          assert last_stream_source == STREAM_SOURCE + "-updated-source"
          worker_wake.set()
  
          # Ccleanup
          stream.stop()
  