emrg: add session._validate_tool_messages tests

tests/test_session.py

@@ -0,0 +1,160 @@
+"""Tests for session._validate_tool_messages."""
+
+import pytest
+
+from emrg.session import _validate_tool_messages
+
+
+class TestValidateToolMessages:
+    """Tests for the _validate_tool_messages safety-net function."""
+
+    def test_empty(self):
+        """Empty list returns empty list."""
+        assert _validate_tool_messages([]) == []
+
+    def test_plain_messages_pass_through(self):
+        """Plain user/assistant messages pass through unchanged."""
+        msgs = [
+            {"role": "user", "content": "hello"},
+            {"role": "assistant", "content": "hi there"},
+        ]
+        assert _validate_tool_messages(msgs) == msgs
+
+    def test_summary_messages_pass_through(self):
+        """Summary-type messages pass through unchanged."""
+        msgs = [
+            {"role": "user", "content": "[Previous conversation summary]\n..."},
+        ]
+        assert _validate_tool_messages(msgs) == msgs
+
+    def test_assistant_with_tool_calls_and_matching_tools(self):
+        """Assistant with tool_calls + matching tool messages: both preserved."""
+        msgs = [
+            {"role": "user", "content": "read foo.txt"},
+            {
+                "role": "assistant",
+                "content": None,
+                "tool_calls": [
+                    {"id": "call_1", "type": "function", "function": {"name": "read", "arguments": "{}"}},
+                ],
+            },
+            {"role": "tool", "tool_call_id": "call_1", "content": "file contents"},
+        ]
+        result = _validate_tool_messages(msgs)
+        assert len(result) == 3
+        assert "tool_calls" in result[1]
+        assert result[1]["tool_calls"][0]["id"] == "call_1"
+        assert result[2]["role"] == "tool"
+
+    def test_assistant_tool_calls_no_matching_tools(self):
+        """Assistant with tool_calls but no matching tool messages: stripped."""
+        msgs = [
+            {"role": "user", "content": "read foo.txt"},
+            {
+                "role": "assistant",
+                "content": "Let me check that.",
+                "tool_calls": [
+                    {"id": "call_1", "type": "function", "function": {"name": "read", "arguments": "{}"}},
+                ],
+            },
+        ]
+        result = _validate_tool_messages(msgs)
+        assert len(result) == 2
+        assert "tool_calls" not in result[1]
+        assert result[1]["content"] == "Let me check that."
+
+    def test_assistant_tool_calls_no_matching_tools_null_content(self):
+        """Assistant with tool_calls, no match, null content → content becomes ''."""
+        msgs = [
+            {
+                "role": "assistant",
+                "content": None,
+                "tool_calls": [
+                    {"id": "call_1", "type": "function", "function": {"name": "read", "arguments": "{}"}},
+                ],
+            },
+        ]
+        result = _validate_tool_messages(msgs)
+        assert len(result) == 1
+        assert "tool_calls" not in result[0]
+        assert result[0]["content"] == ""
+
+    def test_orphaned_tool_messages_removed(self):
+        """Tool messages without preceding assistant tool_calls are stripped."""
+        msgs = [
+            {"role": "user", "content": "hello"},
+            {"role": "tool", "tool_call_id": "orphan_1", "content": "orphan result"},
+            {"role": "assistant", "content": "done"},
+        ]
+        result = _validate_tool_messages(msgs)
+        assert len(result) == 2
+        assert result[0]["role"] == "user"
+        assert result[1]["role"] == "assistant"
+
+    def test_partial_match_valid_kept_invalid_stripped(self):
+        """Multiple tool_calls, only some have matching tool messages."""
+        msgs = [
+            {"role": "user", "content": "do things"},
+            {
+                "role": "assistant",
+                "content": None,
+                "tool_calls": [
+                    {"id": "call_1", "type": "function", "function": {"name": "read", "arguments": "{}"}},
+                    {"id": "call_2", "type": "function", "function": {"name": "write", "arguments": "{}"}},
+                ],
+            },
+            {"role": "tool", "tool_call_id": "call_1", "content": "result 1"},
+        ]
+        result = _validate_tool_messages(msgs)
+        assert len(result) == 3
+        assert len(result[1]["tool_calls"]) == 1
+        assert result[1]["tool_calls"][0]["id"] == "call_1"
+        assert result[2]["tool_call_id"] == "call_1"
+
+    def test_multiple_assistant_tool_blocks(self):
+        """Two separate assistant+tool blocks, both preserved."""
+        msgs = [
+            {"role": "user", "content": "read a and b"},
+            {
+                "role": "assistant",
+                "content": None,
+                "tool_calls": [
+                    {"id": "call_a", "type": "function", "function": {"name": "read", "arguments": "{}"}},
+                ],
+            },
+            {"role": "tool", "tool_call_id": "call_a", "content": "content a"},
+            {
+                "role": "assistant",
+                "content": None,
+                "tool_calls": [
+                    {"id": "call_b", "type": "function", "function": {"name": "read", "arguments": "{}"}},
+                ],
+            },
+            {"role": "tool", "tool_call_id": "call_b", "content": "content b"},
+            {"role": "assistant", "content": "here you go"},
+        ]
+        result = _validate_tool_messages(msgs)
+        assert len(result) == 6
+        assert result[1]["tool_calls"][0]["id"] == "call_a"
+        assert result[3]["tool_calls"][0]["id"] == "call_b"
+
+    def test_mixed_block_one_valid_one_orphaned(self):
+        """First assistant+tool valid, second assistant has orphaned tools."""
+        msgs = [
+            {"role": "user", "content": "hi"},
+            {
+                "role": "assistant",
+                "content": None,
+                "tool_calls": [
+                    {"id": "call_ok", "type": "function", "function": {"name": "read", "arguments": "{}"}},
+                ],
+            },
+            {"role": "tool", "tool_call_id": "call_ok", "content": "done"},
+            # Orphaned tool message — no preceding assistant tool_calls
+            {"role": "tool", "tool_call_id": "bad_call", "content": "stale"},
+            {"role": "assistant", "content": "all done"},
+        ]
+        result = _validate_tool_messages(msgs)
+        assert len(result) == 4  # user + assistant+tool + assistant
+        assert result[2]["tool_call_id"] == "call_ok"
+        assert result[3]["content"] == "all done"