test/agent: cover merge_stream_tool_calls accumulation

tests/test_agent/test_stream_merge.py

@@ -0,0 +1,25 @@
+from __future__ import annotations
+
+from plyngent.lmproto.openai_compatible.client import merge_stream_tool_calls
+
+
+def test_merge_stream_tool_calls_accumulates_arguments() -> None:
+    lines = [
+        b'{"choices":[{"index":0,"delta":{"tool_calls":[{"index":0,"id":"c1","type":"function","function":{"name":"add","arguments":""}}]}}]}',
+        b'{"choices":[{"index":0,"delta":{"tool_calls":[{"index":0,"function":{"arguments":"{\\"a\\":"}}]}}]}',
+        b'{"choices":[{"index":0,"delta":{"tool_calls":[{"index":0,"function":{"arguments":"1}"}}]},"finish_reason":"tool_calls"}]}',
+    ]
+    calls = merge_stream_tool_calls(lines)
+    assert len(calls) == 1
+    assert calls[0].id == "c1"
+    assert calls[0].function.name == "add"
+    assert calls[0].function.arguments == '{"a":1}'
+
+
+def test_merge_stream_tool_calls_multiple_indices() -> None:
+    lines = [
+        b'{"choices":[{"delta":{"tool_calls":[{"index":0,"id":"a","type":"function","function":{"name":"f1","arguments":"{}"}}]}}]}',
+        b'{"choices":[{"delta":{"tool_calls":[{"index":1,"id":"b","type":"function","function":{"name":"f2","arguments":"[]"}}]}}]}',
+    ]
+    calls = merge_stream_tool_calls(lines)
+    assert {c.function.name for c in calls} == {"f1", "f2"}