[baobao] good first issue: Add edge-case unit tests for BM25 keyword parsing

tests/fixtures/sample_documents.json

@@ -0,0 +1,22 @@
+[
+  {
+    "id": "1",
+    "content": "Python is a great programming language."
+  },
+  {
+    "id": "2",
+    "content": "Solidity is used for smart contracts."
+  },
+  {
+    "id": "3",
+    "content": "JavaScript powers the web."
+  },
+  {
+    "id": "4",
+    "content": "Edge cases are important for robust software."
+  },
+  {
+    "id": "5",
+    "content": "Unit tests ensure code quality."
+  }
+]

tests/test_search_edge_cases.py

@@ -0,0 +1,114 @@
+import pytest
+import os
+import sys
+from pathlib import Path
+
+# Add the project root to the path to allow imports
+project_root = Path(__file__).parent.parent
+sys.path.insert(0, str(project_root))
+
+from search_knowledge import bm25_search, parse_query
+
+# Fixture data directory
+FIXTURES_DIR = project_root / "tests" / "fixtures"
+
+@pytest.fixture
+def sample_documents():
+    """Load sample documents for testing."""
+    # In a real scenario, this might load from a JSON file or DB
+    # For this test, we define a static set of documents
+    return [
+        {"id": "1", "content": "Python is a great programming language."},
+        {"id": "2", "content": "Solidity is used for smart contracts."},
+        {"id": "3", "content": "JavaScript powers the web."},
+        {"id": "4", "content": "Edge cases are important for robust software."},
+        {"id": "5", "content": "Unit tests ensure code quality."},
+    ]
+
+def test_empty_query_string(sample_documents):
+    """Test behavior when query string is empty."""
+    # parse_query should return an empty list or handle gracefully
+    parsed = parse_query("")
+    assert parsed == []
+
+    # bm25_search should return empty results or handle gracefully
+    results = bm25_search(sample_documents, "")
+    assert results == []
+
+def test_special_characters_in_query(sample_documents):
+    """Test handling of special characters in query."""
+    special_queries = [
+        "!!!",
+        "@#$%",
+        "test<>script",
+        "query with (parentheses)",
+        "query with [brackets]",
+        "query with {braces}",
+        "query with | pipe",
+        "query with & ampersand",
+        "query with * asterisk",
+        "query with ? question",
+    ]
+
+    for query in special_queries:
+        # Should not raise an exception
+        parsed = parse_query(query)
+        # Results should be empty or contain only valid tokens if any
+        results = bm25_search(sample_documents, query)
+        # Just ensure no crash occurs
+        assert isinstance(results, list)
+
+def test_single_word_match(sample_documents):
+    """Test matching with a single word query."""
+    test_cases = [
+        ("Python", ["1"]),
+        ("Solidity", ["2"]),
+        ("JavaScript", ["3"]),
+        ("Edge", ["4"]),
+        ("tests", ["5"]),
+    ]
+
+    for query, expected_ids in test_cases:
+        results = bm25_search(sample_documents, query)
+        result_ids = [r["id"] for r in results]
+        # Check that the expected document is in results
+        for expected_id in expected_ids:
+            assert expected_id in result_ids
+
+def test_extremely_long_query(sample_documents):
+    """Test handling of extremely long query (>500 chars)."""
+    # Create a query longer than 500 characters
+    long_word = "a" * 100
+    long_query = f"{long_word} {long_word} {long_word} {long_word} {long_word} {long_word}"
+    assert len(long_query) > 500
+
+    # Should not raise an exception
+    parsed = parse_query(long_query)
+    results = bm25_search(sample_documents, long_query)
+
+    # Should return a list (possibly empty if no matches)
+    assert isinstance(results, list)
+
+def test_mixed_case_query(sample_documents):
+    """Test that queries are case-insensitive."""
+    results_lower = bm25_search(sample_documents, "python")
+    results_upper = bm25_search(sample_documents, "PYTHON")
+    results_mixed = bm25_search(sample_documents, "PyThOn")
+
+    # All should return the same results
+    assert len(results_lower) == len(results_upper) == len(results_mixed)
+    if results_lower:
+        assert results_lower[0]["id"] == results_upper[0]["id"] == results_mixed[0]["id"]
+
+def test_query_with_extra_whitespace(sample_documents):
+    """Test handling of queries with extra whitespace."""
+    query_with_spaces = "   python   is   great   "
+    query_normal = "python is great"
+
+    results_spaces = bm25_search(sample_documents, query_with_spaces)
+    results_normal = bm25_search(sample_documents, query_normal)
+
+    # Should return same results
+    assert len(results_spaces) == len(results_normal)
+    if results_spaces:
+        assert results_spaces[0]["id"] == results_normal[0]["id"]