fix: deep research runs the prompt's example queries when the model echoes them (#1666)

tests/test_deep_research_parse_json_array_echo.py

@@ -0,0 +1,54 @@
+"""_parse_json_array must not inject the prompt's example queries.
+
+The query-generation prompt ends with an Example: [...] array. Weak models
+echo that example before emitting the real array. The old parser's greedy
+regex spanned both arrays, failed to parse, and the repair fallback then
+harvested EVERY quoted string from the reply, so the engine ran literal
+searches for "query one" / "query two" / "query three".
+"""
+
+from src.deep_research import DeepResearcher
+
+
+def _dr():
+    # _parse_json_array only touches self via the static _strip_code_block,
+    # so skip the heavy __init__.
+    return object.__new__(DeepResearcher)
+
+
+def test_example_echo_returns_only_the_real_array():
+    text = (
+        'Example: ["query one", "query two", "query three"]\n'
+        '["impact of AI on jobs", "AI automation statistics 2026"]'
+    )
+    assert _dr()._parse_json_array(text) == [
+        "impact of AI on jobs",
+        "AI automation statistics 2026",
+    ]
+
+
+def test_truncated_real_array_after_example_skips_example():
+    text = 'Example: ["query one", "query two"]\n["real query a", "real query b'
+    assert _dr()._parse_json_array(text) == ["real query a"]
+
+
+def test_plain_array_still_parses():
+    assert _dr()._parse_json_array('["a", "b"]') == ["a", "b"]
+
+
+def test_array_in_prose_still_parses():
+    out = _dr()._parse_json_array('Here are the queries: ["a", "b"] hope that helps')
+    assert out == ["a", "b"]
+
+
+def test_truncated_single_array_still_repaired():
+    out = _dr()._parse_json_array('["query one", "query two", "query thr')
+    assert out == ["query one", "query two"]
+
+
+def test_code_fenced_array_still_parses():
+    assert _dr()._parse_json_array('```json\n["a", "b"]\n```') == ["a", "b"]
+
+
+def test_no_array_returns_empty():
+    assert _dr()._parse_json_array("no array here") == []