test: 테스트 커버리지 77% → 80% 달성 (issue #204)

신규/추가 테스트:
- tests/test_logging_config.py: JSONFormatter, setup_logging 전체 커버 (14줄)
- tests/test_strategies_base.py: BaseStrategy 추상 클래스 커버 (6줄)
- tests/test_backup.py: BackupExporter 미커버 경로(빈 CSV, compress=True CSV,
  포맷 실패 로깅, 기본 formats) + CloudStorage boto3 모킹 테스트 20개 (113줄)
- tests/test_context.py: ContextSummarizer 전체 커버 22개 테스트 (50줄)

총 815개 테스트 통과, TOTAL 커버리지 80% (1046줄 미커버 / 5225줄 전체)

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

tests/test_backup.py

@@ -3,9 +3,11 @@
 from __future__ import annotations
 
 import sqlite3
+import sys
 import tempfile
 from datetime import UTC, datetime, timedelta
 from pathlib import Path
+from unittest.mock import MagicMock, patch
 
 import pytest
 
@@ -363,3 +365,435 @@ class TestHealthMonitor:
         assert "timestamp" in report
         assert "checks" in report
         assert len(report["checks"]) == 3
+
+
+# ---------------------------------------------------------------------------
+# BackupExporter — additional coverage for previously uncovered branches
+# ---------------------------------------------------------------------------
+
+
+@pytest.fixture
+def empty_db(tmp_path: Path) -> Path:
+    """Create a temporary database with NO trade records."""
+    db_path = tmp_path / "empty_trades.db"
+    conn = sqlite3.connect(str(db_path))
+    conn.execute(
+        """CREATE TABLE trades (
+            id INTEGER PRIMARY KEY AUTOINCREMENT,
+            timestamp TEXT NOT NULL,
+            stock_code TEXT NOT NULL,
+            action TEXT NOT NULL,
+            quantity INTEGER NOT NULL,
+            price REAL NOT NULL,
+            confidence INTEGER NOT NULL,
+            rationale TEXT,
+            pnl REAL DEFAULT 0.0
+        )"""
+    )
+    conn.commit()
+    conn.close()
+    return db_path
+
+
+class TestBackupExporterAdditional:
+    """Cover branches missed in the original TestBackupExporter suite."""
+
+    def test_export_all_default_formats(self, temp_db: Path, tmp_path: Path) -> None:
+        """export_all with formats=None must default to JSON+CSV+Parquet path."""
+        exporter = BackupExporter(str(temp_db))
+        # formats=None triggers the default list assignment (line 62)
+        results = exporter.export_all(tmp_path / "out", formats=None, compress=False)
+        # JSON and CSV must always succeed; Parquet needs pyarrow
+        assert ExportFormat.JSON in results
+        assert ExportFormat.CSV in results
+
+    def test_export_all_logs_error_on_failure(
+        self, temp_db: Path, tmp_path: Path
+    ) -> None:
+        """export_all must log an error and continue when one format fails."""
+        exporter = BackupExporter(str(temp_db))
+        # Patch _export_format to raise on JSON, succeed on CSV
+        original = exporter._export_format
+
+        def failing_export(fmt, *args, **kwargs):  # type: ignore[no-untyped-def]
+            if fmt == ExportFormat.JSON:
+                raise RuntimeError("simulated failure")
+            return original(fmt, *args, **kwargs)
+
+        exporter._export_format = failing_export  # type: ignore[method-assign]
+        results = exporter.export_all(
+            tmp_path / "out",
+            formats=[ExportFormat.JSON, ExportFormat.CSV],
+            compress=False,
+        )
+        # JSON failed → not in results; CSV succeeded → in results
+        assert ExportFormat.JSON not in results
+        assert ExportFormat.CSV in results
+
+    def test_export_csv_empty_trades_no_compress(
+        self, empty_db: Path, tmp_path: Path
+    ) -> None:
+        """CSV export with no trades and compress=False must write header row only."""
+        exporter = BackupExporter(str(empty_db))
+        results = exporter.export_all(
+            tmp_path / "out",
+            formats=[ExportFormat.CSV],
+            compress=False,
+        )
+        assert ExportFormat.CSV in results
+        out = results[ExportFormat.CSV]
+        assert out.exists()
+        content = out.read_text()
+        assert "timestamp" in content
+
+    def test_export_csv_empty_trades_compressed(
+        self, empty_db: Path, tmp_path: Path
+    ) -> None:
+        """CSV export with no trades and compress=True must write gzipped header."""
+        import gzip
+
+        exporter = BackupExporter(str(empty_db))
+        results = exporter.export_all(
+            tmp_path / "out",
+            formats=[ExportFormat.CSV],
+            compress=True,
+        )
+        assert ExportFormat.CSV in results
+        out = results[ExportFormat.CSV]
+        assert out.suffix == ".gz"
+        with gzip.open(out, "rt", encoding="utf-8") as f:
+            content = f.read()
+        assert "timestamp" in content
+
+    def test_export_csv_with_data_compressed(
+        self, temp_db: Path, tmp_path: Path
+    ) -> None:
+        """CSV export with data and compress=True must write gzipped rows."""
+        import gzip
+
+        exporter = BackupExporter(str(temp_db))
+        results = exporter.export_all(
+            tmp_path / "out",
+            formats=[ExportFormat.CSV],
+            compress=True,
+        )
+        assert ExportFormat.CSV in results
+        out = results[ExportFormat.CSV]
+        with gzip.open(out, "rt", encoding="utf-8") as f:
+            lines = f.readlines()
+        # Header + 3 data rows
+        assert len(lines) == 4
+
+    def test_export_parquet_raises_import_error_without_pyarrow(
+        self, temp_db: Path, tmp_path: Path
+    ) -> None:
+        """Parquet export must raise ImportError when pyarrow is not installed."""
+        exporter = BackupExporter(str(temp_db))
+        with patch.dict(sys.modules, {"pyarrow": None, "pyarrow.parquet": None}):
+            try:
+                import pyarrow  # noqa: F401
+                pytest.skip("pyarrow is installed; cannot test ImportError path")
+            except ImportError:
+                pass
+            results = exporter.export_all(
+                tmp_path / "out",
+                formats=[ExportFormat.PARQUET],
+                compress=False,
+            )
+            # Parquet export fails gracefully; result dict should not contain it
+            assert ExportFormat.PARQUET not in results
+
+
+# ---------------------------------------------------------------------------
+# CloudStorage — mocked boto3 tests
+# ---------------------------------------------------------------------------
+
+
+@pytest.fixture
+def mock_boto3_module():
+    """Inject a fake boto3 into sys.modules for the duration of the test."""
+    mock = MagicMock()
+    with patch.dict(sys.modules, {"boto3": mock}):
+        yield mock
+
+
+@pytest.fixture
+def s3_config():
+    """Minimal S3Config for tests."""
+    from src.backup.cloud_storage import S3Config
+
+    return S3Config(
+        endpoint_url="http://localhost:9000",
+        access_key="minioadmin",
+        secret_key="minioadmin",
+        bucket_name="test-bucket",
+        region="us-east-1",
+    )
+
+
+class TestCloudStorage:
+    """Test CloudStorage using mocked boto3."""
+
+    def test_init_creates_s3_client(self, mock_boto3_module, s3_config) -> None:
+        """CloudStorage.__init__ must call boto3.client with the correct args."""
+        from src.backup.cloud_storage import CloudStorage
+
+        storage = CloudStorage(s3_config)
+        mock_boto3_module.client.assert_called_once()
+        call_kwargs = mock_boto3_module.client.call_args[1]
+        assert call_kwargs["aws_access_key_id"] == "minioadmin"
+        assert call_kwargs["aws_secret_access_key"] == "minioadmin"
+        assert storage.config == s3_config
+
+    def test_init_raises_if_boto3_missing(self, s3_config) -> None:
+        """CloudStorage.__init__ must raise ImportError when boto3 is absent."""
+        with patch.dict(sys.modules, {"boto3": None}):  # type: ignore[dict-item]
+            with pytest.raises((ImportError, TypeError)):
+                # Re-import to trigger the try/except inside __init__
+                import importlib
+
+                import src.backup.cloud_storage as m
+
+                importlib.reload(m)
+                m.CloudStorage(s3_config)
+
+    def test_upload_file_success(
+        self, mock_boto3_module, s3_config, tmp_path: Path
+    ) -> None:
+        """upload_file must call client.upload_file and return the object key."""
+        from src.backup.cloud_storage import CloudStorage
+
+        test_file = tmp_path / "backup.json.gz"
+        test_file.write_bytes(b"data")
+
+        storage = CloudStorage(s3_config)
+        key = storage.upload_file(test_file, object_key="backups/backup.json.gz")
+
+        assert key == "backups/backup.json.gz"
+        storage.client.upload_file.assert_called_once()
+
+    def test_upload_file_default_key(
+        self, mock_boto3_module, s3_config, tmp_path: Path
+    ) -> None:
+        """upload_file without object_key must use the filename as key."""
+        from src.backup.cloud_storage import CloudStorage
+
+        test_file = tmp_path / "myfile.gz"
+        test_file.write_bytes(b"data")
+
+        storage = CloudStorage(s3_config)
+        key = storage.upload_file(test_file)
+
+        assert key == "myfile.gz"
+
+    def test_upload_file_not_found(
+        self, mock_boto3_module, s3_config, tmp_path: Path
+    ) -> None:
+        """upload_file must raise FileNotFoundError for missing files."""
+        from src.backup.cloud_storage import CloudStorage
+
+        storage = CloudStorage(s3_config)
+        with pytest.raises(FileNotFoundError):
+            storage.upload_file(tmp_path / "nonexistent.gz")
+
+    def test_upload_file_propagates_client_error(
+        self, mock_boto3_module, s3_config, tmp_path: Path
+    ) -> None:
+        """upload_file must re-raise exceptions from the boto3 client."""
+        from src.backup.cloud_storage import CloudStorage
+
+        test_file = tmp_path / "backup.gz"
+        test_file.write_bytes(b"data")
+
+        storage = CloudStorage(s3_config)
+        storage.client.upload_file.side_effect = RuntimeError("network error")
+
+        with pytest.raises(RuntimeError, match="network error"):
+            storage.upload_file(test_file)
+
+    def test_download_file_success(
+        self, mock_boto3_module, s3_config, tmp_path: Path
+    ) -> None:
+        """download_file must call client.download_file and return local path."""
+        from src.backup.cloud_storage import CloudStorage
+
+        storage = CloudStorage(s3_config)
+        dest = tmp_path / "downloads" / "backup.gz"
+
+        result = storage.download_file("backups/backup.gz", dest)
+
+        assert result == dest
+        storage.client.download_file.assert_called_once()
+
+    def test_download_file_propagates_error(
+        self, mock_boto3_module, s3_config, tmp_path: Path
+    ) -> None:
+        """download_file must re-raise exceptions from the boto3 client."""
+        from src.backup.cloud_storage import CloudStorage
+
+        storage = CloudStorage(s3_config)
+        storage.client.download_file.side_effect = RuntimeError("timeout")
+
+        with pytest.raises(RuntimeError, match="timeout"):
+            storage.download_file("key", tmp_path / "dest.gz")
+
+    def test_list_files_returns_objects(
+        self, mock_boto3_module, s3_config
+    ) -> None:
+        """list_files must return parsed file metadata from S3 response."""
+        from datetime import timezone
+
+        from src.backup.cloud_storage import CloudStorage
+
+        storage = CloudStorage(s3_config)
+        storage.client.list_objects_v2.return_value = {
+            "Contents": [
+                {
+                    "Key": "backups/a.gz",
+                    "Size": 1024,
+                    "LastModified": datetime(2026, 1, 1, tzinfo=timezone.utc),
+                    "ETag": '"abc123"',
+                }
+            ]
+        }
+
+        files = storage.list_files(prefix="backups/")
+        assert len(files) == 1
+        assert files[0]["key"] == "backups/a.gz"
+        assert files[0]["size_bytes"] == 1024
+
+    def test_list_files_empty_bucket(
+        self, mock_boto3_module, s3_config
+    ) -> None:
+        """list_files must return empty list when bucket has no objects."""
+        from src.backup.cloud_storage import CloudStorage
+
+        storage = CloudStorage(s3_config)
+        storage.client.list_objects_v2.return_value = {}
+
+        files = storage.list_files()
+        assert files == []
+
+    def test_list_files_propagates_error(
+        self, mock_boto3_module, s3_config
+    ) -> None:
+        """list_files must re-raise exceptions from the boto3 client."""
+        from src.backup.cloud_storage import CloudStorage
+
+        storage = CloudStorage(s3_config)
+        storage.client.list_objects_v2.side_effect = RuntimeError("auth error")
+
+        with pytest.raises(RuntimeError):
+            storage.list_files()
+
+    def test_delete_file_success(
+        self, mock_boto3_module, s3_config
+    ) -> None:
+        """delete_file must call client.delete_object with the correct key."""
+        from src.backup.cloud_storage import CloudStorage
+
+        storage = CloudStorage(s3_config)
+        storage.delete_file("backups/old.gz")
+        storage.client.delete_object.assert_called_once_with(
+            Bucket="test-bucket", Key="backups/old.gz"
+        )
+
+    def test_delete_file_propagates_error(
+        self, mock_boto3_module, s3_config
+    ) -> None:
+        """delete_file must re-raise exceptions from the boto3 client."""
+        from src.backup.cloud_storage import CloudStorage
+
+        storage = CloudStorage(s3_config)
+        storage.client.delete_object.side_effect = RuntimeError("permission denied")
+
+        with pytest.raises(RuntimeError):
+            storage.delete_file("backups/old.gz")
+
+    def test_get_storage_stats_success(
+        self, mock_boto3_module, s3_config
+    ) -> None:
+        """get_storage_stats must aggregate file sizes correctly."""
+        from datetime import timezone
+
+        from src.backup.cloud_storage import CloudStorage
+
+        storage = CloudStorage(s3_config)
+        storage.client.list_objects_v2.return_value = {
+            "Contents": [
+                {
+                    "Key": "a.gz",
+                    "Size": 1024 * 1024,
+                    "LastModified": datetime(2026, 1, 1, tzinfo=timezone.utc),
+                    "ETag": '"x"',
+                },
+                {
+                    "Key": "b.gz",
+                    "Size": 1024 * 1024,
+                    "LastModified": datetime(2026, 1, 2, tzinfo=timezone.utc),
+                    "ETag": '"y"',
+                },
+            ]
+        }
+
+        stats = storage.get_storage_stats()
+        assert stats["total_files"] == 2
+        assert stats["total_size_bytes"] == 2 * 1024 * 1024
+        assert stats["total_size_mb"] == pytest.approx(2.0)
+
+    def test_get_storage_stats_on_error(
+        self, mock_boto3_module, s3_config
+    ) -> None:
+        """get_storage_stats must return error dict without raising on failure."""
+        from src.backup.cloud_storage import CloudStorage
+
+        storage = CloudStorage(s3_config)
+        storage.client.list_objects_v2.side_effect = RuntimeError("no connection")
+
+        stats = storage.get_storage_stats()
+        assert "error" in stats
+        assert stats["total_files"] == 0
+
+    def test_verify_connection_success(
+        self, mock_boto3_module, s3_config
+    ) -> None:
+        """verify_connection must return True when head_bucket succeeds."""
+        from src.backup.cloud_storage import CloudStorage
+
+        storage = CloudStorage(s3_config)
+        result = storage.verify_connection()
+        assert result is True
+
+    def test_verify_connection_failure(
+        self, mock_boto3_module, s3_config
+    ) -> None:
+        """verify_connection must return False when head_bucket raises."""
+        from src.backup.cloud_storage import CloudStorage
+
+        storage = CloudStorage(s3_config)
+        storage.client.head_bucket.side_effect = RuntimeError("no such bucket")
+
+        result = storage.verify_connection()
+        assert result is False
+
+    def test_enable_versioning(
+        self, mock_boto3_module, s3_config
+    ) -> None:
+        """enable_versioning must call put_bucket_versioning."""
+        from src.backup.cloud_storage import CloudStorage
+
+        storage = CloudStorage(s3_config)
+        storage.enable_versioning()
+        storage.client.put_bucket_versioning.assert_called_once()
+
+    def test_enable_versioning_propagates_error(
+        self, mock_boto3_module, s3_config
+    ) -> None:
+        """enable_versioning must re-raise exceptions from the boto3 client."""
+        from src.backup.cloud_storage import CloudStorage
+
+        storage = CloudStorage(s3_config)
+        storage.client.put_bucket_versioning.side_effect = RuntimeError("denied")
+
+        with pytest.raises(RuntimeError):
+            storage.enable_versioning()