Streaming rag responses (#568)

* Tech spec for streaming RAG

* Support for streaming Graph/Doc RAG

tests/utils/__init__.py

@@ -0,0 +1,29 @@
+"""Test utilities for TrustGraph tests"""
+
+from .streaming_assertions import (
+    assert_streaming_chunks_valid,
+    assert_streaming_sequence,
+    assert_agent_streaming_chunks,
+    assert_rag_streaming_chunks,
+    assert_streaming_completion,
+    assert_streaming_content_matches,
+    assert_no_empty_chunks,
+    assert_streaming_error_handled,
+    assert_chunk_types_valid,
+    assert_streaming_latency_acceptable,
+    assert_callback_invoked,
+)
+
+__all__ = [
+    "assert_streaming_chunks_valid",
+    "assert_streaming_sequence",
+    "assert_agent_streaming_chunks",
+    "assert_rag_streaming_chunks",
+    "assert_streaming_completion",
+    "assert_streaming_content_matches",
+    "assert_no_empty_chunks",
+    "assert_streaming_error_handled",
+    "assert_chunk_types_valid",
+    "assert_streaming_latency_acceptable",
+    "assert_callback_invoked",
+]

tests/utils/streaming_assertions.py

@@ -0,0 +1,218 @@
+"""
+Streaming test assertion helpers
+
+Provides reusable assertion functions for validating streaming behavior
+across different TrustGraph services.
+"""
+
+from typing import List, Dict, Any, Optional
+
+
+def assert_streaming_chunks_valid(chunks: List[Any], min_chunks: int = 1):
+    """
+    Assert that streaming chunks are valid and non-empty.
+
+    Args:
+        chunks: List of streaming chunks
+        min_chunks: Minimum number of expected chunks
+    """
+    assert len(chunks) >= min_chunks, f"Expected at least {min_chunks} chunks, got {len(chunks)}"
+    assert all(chunk is not None for chunk in chunks), "All chunks should be non-None"
+
+
+def assert_streaming_sequence(chunks: List[Dict[str, Any]], expected_sequence: List[str], key: str = "chunk_type"):
+    """
+    Assert that streaming chunks follow an expected sequence.
+
+    Args:
+        chunks: List of chunk dictionaries
+        expected_sequence: Expected sequence of chunk types/values
+        key: Dictionary key to check (default: "chunk_type")
+    """
+    actual_sequence = [chunk.get(key) for chunk in chunks if key in chunk]
+    assert actual_sequence == expected_sequence, \
+        f"Expected sequence {expected_sequence}, got {actual_sequence}"
+
+
+def assert_agent_streaming_chunks(chunks: List[Dict[str, Any]]):
+    """
+    Assert that agent streaming chunks have valid structure.
+
+    Validates:
+    - All chunks have chunk_type field
+    - All chunks have content field
+    - All chunks have end_of_message field
+    - All chunks have end_of_dialog field
+    - Last chunk has end_of_dialog=True
+
+    Args:
+        chunks: List of agent streaming chunk dictionaries
+    """
+    assert len(chunks) > 0, "Expected at least one chunk"
+
+    for i, chunk in enumerate(chunks):
+        assert "chunk_type" in chunk, f"Chunk {i} missing chunk_type"
+        assert "content" in chunk, f"Chunk {i} missing content"
+        assert "end_of_message" in chunk, f"Chunk {i} missing end_of_message"
+        assert "end_of_dialog" in chunk, f"Chunk {i} missing end_of_dialog"
+
+        # Validate chunk_type values
+        valid_types = ["thought", "action", "observation", "final-answer"]
+        assert chunk["chunk_type"] in valid_types, \
+            f"Invalid chunk_type '{chunk['chunk_type']}' at index {i}"
+
+    # Last chunk should signal end of dialog
+    assert chunks[-1]["end_of_dialog"] is True, \
+        "Last chunk should have end_of_dialog=True"
+
+
+def assert_rag_streaming_chunks(chunks: List[Dict[str, Any]]):
+    """
+    Assert that RAG streaming chunks have valid structure.
+
+    Validates:
+    - All chunks except last have chunk field
+    - All chunks have end_of_stream field
+    - Last chunk has end_of_stream=True
+    - Last chunk may have response field with complete text
+
+    Args:
+        chunks: List of RAG streaming chunk dictionaries
+    """
+    assert len(chunks) > 0, "Expected at least one chunk"
+
+    for i, chunk in enumerate(chunks):
+        assert "end_of_stream" in chunk, f"Chunk {i} missing end_of_stream"
+
+        if i < len(chunks) - 1:
+            # Non-final chunks should have chunk content and end_of_stream=False
+            assert "chunk" in chunk, f"Chunk {i} missing chunk field"
+            assert chunk["end_of_stream"] is False, \
+                f"Non-final chunk {i} should have end_of_stream=False"
+        else:
+            # Final chunk should have end_of_stream=True
+            assert chunk["end_of_stream"] is True, \
+                "Last chunk should have end_of_stream=True"
+
+
+def assert_streaming_completion(chunks: List[Dict[str, Any]], expected_complete_flag: str = "end_of_stream"):
+    """
+    Assert that streaming completed properly.
+
+    Args:
+        chunks: List of streaming chunk dictionaries
+        expected_complete_flag: Name of the completion flag field
+    """
+    assert len(chunks) > 0, "Expected at least one chunk"
+
+    # Check that all but last chunk have completion flag = False
+    for i, chunk in enumerate(chunks[:-1]):
+        assert chunk.get(expected_complete_flag) is False, \
+            f"Non-final chunk {i} should have {expected_complete_flag}=False"
+
+    # Check that last chunk has completion flag = True
+    assert chunks[-1].get(expected_complete_flag) is True, \
+        f"Final chunk should have {expected_complete_flag}=True"
+
+
+def assert_streaming_content_matches(chunks: List, expected_content: str, content_key: str = "chunk"):
+    """
+    Assert that concatenated streaming chunks match expected content.
+
+    Args:
+        chunks: List of streaming chunks (strings or dicts)
+        expected_content: Expected complete content after concatenation
+        content_key: Dictionary key for content (used if chunks are dicts)
+    """
+    if isinstance(chunks[0], dict):
+        # Extract content from chunk dictionaries
+        content_chunks = [
+            chunk.get(content_key, "")
+            for chunk in chunks
+            if chunk.get(content_key) is not None
+        ]
+        actual_content = "".join(content_chunks)
+    else:
+        # Chunks are already strings
+        actual_content = "".join(chunks)
+
+    assert actual_content == expected_content, \
+        f"Expected content '{expected_content}', got '{actual_content}'"
+
+
+def assert_no_empty_chunks(chunks: List[Dict[str, Any]], content_key: str = "content"):
+    """
+    Assert that no chunks have empty content (except final chunk if it's completion marker).
+
+    Args:
+        chunks: List of streaming chunk dictionaries
+        content_key: Dictionary key for content
+    """
+    for i, chunk in enumerate(chunks[:-1]):
+        content = chunk.get(content_key)
+        assert content is not None and len(content) > 0, \
+            f"Chunk {i} has empty content"
+
+
+def assert_streaming_error_handled(chunks: List[Dict[str, Any]], error_flag: str = "error"):
+    """
+    Assert that streaming error was properly signaled.
+
+    Args:
+        chunks: List of streaming chunk dictionaries
+        error_flag: Name of the error flag field
+    """
+    # Check that at least one chunk has error flag
+    has_error = any(chunk.get(error_flag) is not None for chunk in chunks)
+    assert has_error, "Expected error flag in at least one chunk"
+
+    # If last chunk has error, should also have completion flag
+    if chunks[-1].get(error_flag):
+        # Check for completion flags (either end_of_stream or end_of_dialog)
+        completion_flags = ["end_of_stream", "end_of_dialog"]
+        has_completion = any(chunks[-1].get(flag) is True for flag in completion_flags)
+        assert has_completion, \
+            "Error chunk should have completion flag set to True"
+
+
+def assert_chunk_types_valid(chunks: List[Dict[str, Any]], valid_types: List[str], type_key: str = "chunk_type"):
+    """
+    Assert that all chunk types are from a valid set.
+
+    Args:
+        chunks: List of streaming chunk dictionaries
+        valid_types: List of valid chunk type values
+        type_key: Dictionary key for chunk type
+    """
+    for i, chunk in enumerate(chunks):
+        chunk_type = chunk.get(type_key)
+        assert chunk_type in valid_types, \
+            f"Chunk {i} has invalid type '{chunk_type}', expected one of {valid_types}"
+
+
+def assert_streaming_latency_acceptable(chunk_timestamps: List[float], max_gap_seconds: float = 5.0):
+    """
+    Assert that streaming latency between chunks is acceptable.
+
+    Args:
+        chunk_timestamps: List of timestamps when chunks were received
+        max_gap_seconds: Maximum acceptable gap between chunks in seconds
+    """
+    assert len(chunk_timestamps) > 1, "Need at least 2 timestamps to check latency"
+
+    for i in range(1, len(chunk_timestamps)):
+        gap = chunk_timestamps[i] - chunk_timestamps[i-1]
+        assert gap <= max_gap_seconds, \
+            f"Gap between chunks {i-1} and {i} is {gap:.2f}s, exceeds max {max_gap_seconds}s"
+
+
+def assert_callback_invoked(mock_callback, min_calls: int = 1):
+    """
+    Assert that a streaming callback was invoked minimum number of times.
+
+    Args:
+        mock_callback: AsyncMock callback object
+        min_calls: Minimum number of expected calls
+    """
+    assert mock_callback.call_count >= min_calls, \
+        f"Expected callback to be called at least {min_calls} times, was called {mock_callback.call_count} times"