Merge pull request #33 from heikomuller/empty-csv

Empty csv

CHANGELOG.md

@@ -79,3 +79,8 @@
 * Add empty document class ``histore.document.mem.Schema``.
 * Change format of serialized archive JSON files.
 * Change internal representation of timestamps.
+
+
+### 0.4.1 - 2021-04-28
+
+* Handle empty CSV files properly.

histore/document/csv/base.py

@@ -160,8 +160,13 @@ def __init__(
                 encoding=self.encoding,
                 none_is=self.none_is
             )
-            header = next(reader)
-            reader.close()
+            try:
+                header = next(reader)
+            except StopIteration:
+                # Empty file. The list of column nmaes is empty.
+                header = []
+            finally:
+                reader.close()
         super(CSVFile, self).__init__(
             columns=header,
             filename=filename,

histore/version.py

@@ -6,4 +6,4 @@
 # file LICENSE for full license details.
 
 """Code version information for histore."""
-__version__ = '0.4.0'
+__version__ = '0.4.1'

tests/document/csv/test_csv_document.py

@@ -7,6 +7,8 @@
 
 """Unit tests for the in-memory document and document reader."""
 
+from pathlib import Path
+
 import os
 
 from histore.document.csv.base import CSVFile
@@ -35,6 +37,13 @@ def test_custom_header(tmpdir):
     with doc.open() as reader:
         rows = [row for _, _, row in reader]
     assert rows == [['A', 'B'], ['1', '2']]
+    # -- An empty document has an empty header.
+    empty_file = os.path.join(tmpdir, 'empty.csv')
+    Path(empty_file).touch()
+    doc = CSVFile(filename=empty_file)
+    assert doc.columns == []
+    doc = CSVFile(filename=empty_file, header=['X', 'Y'])
+    assert doc.columns == ['X', 'Y']
 
 
 def test_document_iterator():