diff --git a/tests/components/stream/test_worker.py b/tests/components/stream/test_worker.py
index d5f5ef653c6..ffbeb44d79e 100644
--- a/tests/components/stream/test_worker.py
+++ b/tests/components/stream/test_worker.py
@@ -149,6 +149,7 @@ class FakePyAvBuffer:
         self.segments = []
         self.audio_packets = []
         self.video_packets = []
+        self.memory_file: io.BytesIO | None = None
 
     def add_stream(self, template=None):
         """Create an output buffer that captures packets for test to examine."""
@@ -171,10 +172,13 @@ class FakePyAvBuffer:
         """Capture a packet for tests to examine."""
         # Forward to appropriate FakeStream
         packet.stream.mux(packet)
+        # Make new init/part data available to the worker
+        self.memory_file.write(b"0")
 
     def close(self):
         """Close the buffer."""
-        return
+        # Make the final segment data available to the worker
+        self.memory_file.write(b"0")
 
     def capture_output_segment(self, segment):
         """Capture the output segment for tests to inspect."""
@@ -201,23 +205,11 @@ class MockPyAv:
     def open(self, stream_source, *args, **kwargs):
         """Return a stream or buffer depending on args."""
         if isinstance(stream_source, io.BytesIO):
+            self.capture_buffer.memory_file = stream_source
             return self.capture_buffer
         return self.container
 
 
-class MockFlushPart:
-    """Class to hold a wrapper function for check_flush_part."""
-
-    # Wrap this method with a preceding write so the BytesIO pointer moves
-    check_flush_part = SegmentBuffer.check_flush_part
-
-    @classmethod
-    def wrapped_check_flush_part(cls, segment_buffer, packet):
-        """Wrap check_flush_part to also advance the memory_file pointer."""
-        segment_buffer._memory_file.write(b"0")
-        return cls.check_flush_part(segment_buffer, packet)
-
-
 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, {})
@@ -230,10 +222,6 @@ async def async_decode_stream(hass, packets, py_av=None):
     with patch("av.open", new=py_av.open), patch(
         "homeassistant.components.stream.core.StreamOutput.put",
         side_effect=py_av.capture_buffer.capture_output_segment,
-    ), patch(
-        "homeassistant.components.stream.worker.SegmentBuffer.check_flush_part",
-        side_effect=MockFlushPart.wrapped_check_flush_part,
-        autospec=True,
     ):
         segment_buffer = SegmentBuffer(stream.outputs)
         stream_worker(STREAM_SOURCE, {}, segment_buffer, threading.Event())
@@ -612,11 +600,7 @@ async def test_update_stream_source(hass):
             worker_wake.wait()
         return py_av.open(stream_source, args, kwargs)
 
-    with patch("av.open", new=blocking_open), patch(
-        "homeassistant.components.stream.worker.SegmentBuffer.check_flush_part",
-        side_effect=MockFlushPart.wrapped_check_flush_part,
-        autospec=True,
-    ):
+    with patch("av.open", new=blocking_open):
         stream.start()
         assert worker_open.wait(TIMEOUT)
         assert last_stream_source == STREAM_SOURCE