Improve TTSService handling of long LLM token outputs

tests/test_simple_text_aggregator.py

@@ -33,3 +33,48 @@ class TestSimpleTextAggregator(unittest.IsolatedAsyncioTestCase):
         assert self.aggregator.text.text == "How are"
         aggregate = await self.aggregator.aggregate("you?")
         assert aggregate.text == "How are you?"
+
+    async def test_word_by_word(self):
+        """Test word-by-word token aggregation (e.g., OpenAI)."""
+        assert await self.aggregator.aggregate("Hello") == None
+        aggregate = await self.aggregator.aggregate("!")
+        assert aggregate.text == "Hello!"
+        assert await self.aggregator.aggregate(" I") == None
+        assert await self.aggregator.aggregate(" am") == None
+        aggregate = await self.aggregator.aggregate(" Doug.")
+        assert aggregate.text == "I am Doug."
+        assert self.aggregator.text.text == ""
+
+    async def test_chunks_with_partial_sentences(self):
+        """Test chunks with partial sentences."""
+        aggregate = await self.aggregator.aggregate("Hey!")
+        assert aggregate.text == "Hey!"
+        aggregate = await self.aggregator.aggregate(" Nice to meet you! So")
+        assert aggregate.text == "Nice to meet you!"
+        assert self.aggregator.text.text == "So"
+        assert await self.aggregator.aggregate(" what") == None
+        aggregate = await self.aggregator.aggregate("'d you like?")
+        assert aggregate.text == "So what'd you like?"
+
+    async def test_multi_sentence_chunk(self):
+        """Test chunks with multiple complete sentences."""
+        aggregate = await self.aggregator.aggregate("Hello! I am Doug. Nice to meet you!")
+        assert aggregate.text == "Hello!"
+        # Drain remaining sentences by calling aggregate("")
+        aggregate = await self.aggregator.aggregate("")
+        assert aggregate.text == "I am Doug."
+        aggregate = await self.aggregator.aggregate("")
+        assert aggregate.text == "Nice to meet you!"
+        assert await self.aggregator.aggregate("") == None
+        assert self.aggregator.text.text == ""
+
+    async def test_aggregate_empty_with_incomplete(self):
+        """Test aggregate('') with incomplete sentence in buffer."""
+        aggregate = await self.aggregator.aggregate("Hello! I am")
+        assert aggregate.text == "Hello!"
+        assert await self.aggregator.aggregate("") == None
+        assert self.aggregator.text.text == "I am"
+
+    async def test_aggregate_empty_buffer(self):
+        """Test aggregate('') with empty buffer."""
+        assert await self.aggregator.aggregate("") == None