test(storage): cover temp cleanup and OSError logging for validate upload

- Download OSError: unlink temp, skip validate_file_reader, log errno
- to_csv OSError: unlink temp, no upload, log errno
- Upload failure after to_csv: temp still unlinked

Made-with: Cursor

Author: chapmanhk

src/webapp/gcsutil_test.py

@@ -1,5 +1,8 @@
 """Tests for gcsutil.StorageControl validation and normalized/raw archive flow."""
 
+import errno
+import os
+import tempfile
 from typing import Any
 from unittest.mock import MagicMock, patch
 
@@ -363,3 +366,108 @@ def assert_csv_at_path(path: str, **kwargs: Any) -> None:
     assert mock_blob.upload_from_filename.call_args.kwargs["content_type"] == (
         "text/csv; charset=utf-8"
     )
+
+
+def test_run_validation_download_oserror_unlinks_temp_and_skips_validate() -> None:
+    """If GCS download fails, temp file is removed and validate_file_reader is not run."""
+    fd, real_path = tempfile.mkstemp(suffix=".csv", prefix="test_dl_oserr_")
+    mock_blob = MagicMock()
+    mock_blob.download_to_filename.side_effect = OSError(
+        errno.ENOSPC, "No space left on device"
+    )
+
+    control = StorageControl()
+    with patch("src.webapp.gcsutil.tempfile.mkstemp", return_value=(fd, real_path)):
+        with patch("src.webapp.gcsutil.validate_file_reader") as mock_validate:
+            with pytest.raises(OSError, match="No space left"):
+                control._run_validation_and_get_normalized_df(
+                    mock_blob,
+                    "school_course.csv",
+                    ["STUDENT"],
+                    {},
+                    None,
+                    "pdp",
+                    None,
+                )
+            mock_validate.assert_not_called()
+
+    assert not os.path.exists(real_path)
+    mock_blob.download_to_filename.assert_called_once_with(real_path)
+
+
+def test_run_validation_download_oserror_logs_errno() -> None:
+    """OSError from download_to_filename is logged with errno before re-raise."""
+    fd, real_path = tempfile.mkstemp(suffix=".csv", prefix="test_dl_log_")
+    mock_blob = MagicMock()
+    mock_blob.download_to_filename.side_effect = OSError(
+        errno.ENOSPC, "No space left on device"
+    )
+
+    control = StorageControl()
+    with patch("src.webapp.gcsutil.tempfile.mkstemp", return_value=(fd, real_path)):
+        with patch("src.webapp.gcsutil.logger") as mock_logger:
+            with pytest.raises(OSError):
+                control._run_validation_and_get_normalized_df(
+                    mock_blob,
+                    "f.csv",
+                    ["STUDENT"],
+                    {},
+                    None,
+                    "pdp",
+                    None,
+                )
+            mock_logger.error.assert_called_once()
+            msg = mock_logger.error.call_args[0][0]
+            assert "download_to_filename failed" in msg
+            assert mock_logger.error.call_args[0][3] == errno.ENOSPC
+
+    assert not os.path.exists(real_path)
+
+
+def test_write_dataframe_to_csv_oserror_unlinks_temp() -> None:
+    """If to_csv fails (e.g. disk full), temp file is removed and upload is not attempted."""
+    fd, real_path = tempfile.mkstemp(suffix=".csv", prefix="test_csv_oserr_")
+    mock_blob = MagicMock()
+    mock_bucket = MagicMock()
+    mock_bucket.blob.return_value = mock_blob
+
+    control = StorageControl()
+    with patch("src.webapp.gcsutil.tempfile.mkstemp", return_value=(fd, real_path)):
+        with patch.object(
+            pd.DataFrame,
+            "to_csv",
+            side_effect=OSError(errno.ENOSPC, "No space left on device"),
+        ):
+            with patch("src.webapp.gcsutil.logger") as mock_logger:
+                with pytest.raises(OSError, match="No space left"):
+                    control._write_dataframe_to_gcs_as_csv(
+                        mock_bucket,
+                        "validated/out.csv",
+                        pd.DataFrame({"a": [1]}),
+                    )
+                mock_logger.error.assert_called_once()
+                assert "to_csv failed" in mock_logger.error.call_args[0][0]
+                assert mock_logger.error.call_args[0][3] == errno.ENOSPC
+
+    assert not os.path.exists(real_path)
+    mock_blob.upload_from_filename.assert_not_called()
+
+
+def test_write_dataframe_upload_failure_still_unlinks_temp() -> None:
+    """If GCS upload fails after to_csv, the local temp file is still deleted."""
+    fd, real_path = tempfile.mkstemp(suffix=".csv", prefix="test_upload_fail_")
+    mock_blob = MagicMock()
+    mock_blob.upload_from_filename.side_effect = RuntimeError("upload failed")
+    mock_bucket = MagicMock()
+    mock_bucket.blob.return_value = mock_blob
+
+    control = StorageControl()
+    with patch("src.webapp.gcsutil.tempfile.mkstemp", return_value=(fd, real_path)):
+        with pytest.raises(RuntimeError, match="upload failed"):
+            control._write_dataframe_to_gcs_as_csv(
+                mock_bucket,
+                "validated/out.csv",
+                pd.DataFrame({"x": [1]}),
+            )
+
+    assert not os.path.exists(real_path)