Add tests for get_usage_stats tool

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: RecoDemo

tests/test_usage_stats.py

@@ -0,0 +1,118 @@
+"""Tests for the get_usage_stats session metrics."""
+
+import time
+
+import pytest
+
+
+@pytest.fixture(autouse=True)
+def _reset_server_state():
+    """Reset server module-level state before each test."""
+    import mcp_codebase_index.server as srv
+
+    srv._session_start = time.time()
+    srv._tool_call_counts.clear()
+    srv._total_chars_returned = 0
+    srv._indexer = None
+    srv._query_fns = None
+    yield
+    srv._tool_call_counts.clear()
+    srv._total_chars_returned = 0
+
+
+class TestFormatDuration:
+    def test_seconds(self):
+        from mcp_codebase_index.server import _format_duration
+
+        assert _format_duration(45) == "45s"
+
+    def test_minutes(self):
+        from mcp_codebase_index.server import _format_duration
+
+        assert _format_duration(125) == "2m 5s"
+
+    def test_hours(self):
+        from mcp_codebase_index.server import _format_duration
+
+        assert _format_duration(3725) == "1h 2m"
+
+
+class TestFormatUsageStats:
+    def test_empty_session(self):
+        from mcp_codebase_index.server import _format_usage_stats
+
+        result = _format_usage_stats()
+        assert "Total queries: 0" in result
+        assert "Total chars returned: 0" in result
+
+    def test_with_tool_calls(self):
+        import mcp_codebase_index.server as srv
+
+        srv._tool_call_counts["find_symbol"] = 5
+        srv._tool_call_counts["get_function_source"] = 3
+        srv._total_chars_returned = 1234
+
+        result = srv._format_usage_stats()
+        assert "Total queries: 8" in result
+        assert "find_symbol: 5" in result
+        assert "get_function_source: 3" in result
+        assert "Total chars returned: 1,234" in result
+
+    def test_usage_stats_call_excluded_from_query_count(self):
+        import mcp_codebase_index.server as srv
+
+        srv._tool_call_counts["find_symbol"] = 3
+        srv._tool_call_counts["get_usage_stats"] = 2
+
+        result = srv._format_usage_stats()
+        assert "Total queries: 3" in result
+        # get_usage_stats should not appear in the per-tool breakdown
+        assert "get_usage_stats" not in result
+
+    def test_with_indexed_project(self, tmp_path):
+        import mcp_codebase_index.server as srv
+        from mcp_codebase_index.project_indexer import ProjectIndexer
+
+        # Create a project with enough source to exceed returned chars
+        (tmp_path / "main.py").write_text("def hello():\n    return 'world'\n" * 100)
+        (tmp_path / "utils.py").write_text("def helper():\n    return 42\n" * 100)
+
+        indexer = ProjectIndexer(str(tmp_path), include_patterns=["**/*.py"])
+        indexer.index()
+        srv._indexer = indexer
+
+        srv._tool_call_counts["find_symbol"] = 5
+        srv._total_chars_returned = 200
+
+        result = srv._format_usage_stats()
+        assert "Total source in index:" in result
+        assert "Estimated token savings:" in result
+
+    def test_token_savings_calculation(self, tmp_path):
+        import mcp_codebase_index.server as srv
+        from mcp_codebase_index.project_indexer import ProjectIndexer
+
+        # Create a project with known size
+        (tmp_path / "big.py").write_text("x = 1\n" * 1000)  # ~6000 chars
+
+        indexer = ProjectIndexer(str(tmp_path), include_patterns=["**/*.py"])
+        indexer.index()
+        srv._indexer = indexer
+
+        srv._tool_call_counts["find_symbol"] = 10
+        srv._total_chars_returned = 500
+
+        result = srv._format_usage_stats()
+        assert "Estimated without indexer:" in result
+        assert "Estimated with indexer:" in result
+        # 500 chars returned vs 6000 * 10 = 60000 naive
+        assert "tokens" in result
+
+    def test_no_savings_section_without_index(self):
+        import mcp_codebase_index.server as srv
+
+        srv._tool_call_counts["find_symbol"] = 3
+        srv._total_chars_returned = 100
+
+        result = srv._format_usage_stats()
+        assert "Estimated token savings:" not in result