csv: Support importing squared CSV spreadsheets.

See the test comment for more rationale.

import2ledger/importers/_csv.py

@@ -43,9 +43,17 @@ class CSVImporterBase:
     Reader = csv.reader
     DictReader = csv.DictReader
 
+    @classmethod
+    def _row_rindex(cls, row, default=None):
+        """Return the index of the last cell in the row that has a value."""
+        for offset, value in enumerate(reversed(row), 1):
+            if value:
+                return len(row) - offset
+        return default
+
     @classmethod
     def _read_header_row(cls, row):
-        return {} if len(row) < cls._HEADER_MAX_LEN else None
+        return {} if cls._row_rindex(row, -1) + 1 < cls._HEADER_MAX_LEN else None
 
     @classmethod
     def _read_header(cls, input_file):

import2ledger/importers/benevity.py

@@ -11,10 +11,10 @@ class _DonationsImporterBase(_csv.CSVImporterBase):
 
     @classmethod
     def _read_header_row(cls, row):
-        row_len = len(row)
-        if row_len > 2:
+        row_rindex = cls._row_rindex(row, -1)
+        if row_rindex > 1:
             return None
-        elif row_len == 2 and row[0] in cls.HEADER_FIELDS:
+        elif row_rindex == 1 and row[0] in cls.HEADER_FIELDS:
             return {cls.HEADER_FIELDS[row[0]]: row[1]}
         else:
             return {}

setup.py

@@ -30,7 +30,7 @@ REQUIREMENTS['tests_require'] = [
 setup(
     name='import2ledger',
     description="Import different sources of financial data to Ledger",
-    version='0.9.2',
+    version='0.9.3',
     author='Brett Smith',
     author_email='brettcsmith@brettcsmith.org',
     license='GNU AGPLv3+',

tests/data/imports.yml

@@ -264,6 +264,8 @@
 
 - source: AmazonAffiliateEarnings.csv
   importer: amazon.EarningsImporter
+  header_rows: 1
+  header_cols: 12
   expect:
     - payee: Amazon
       date: !!python/object/apply:datetime.date [2016, 12, 20]
@@ -276,6 +278,8 @@
 
 - source: Benevity2018.csv
   importer: benevity.Donations2018Importer
+  header_rows: 11
+  header_cols: 17
   expect:
     - date: !!python/object/apply:datetime.date [2017, 10, 28]
       currency: USD
@@ -366,6 +370,8 @@
 
 - source: Benevity2019.csv
   importer: benevity.Donations2019Importer
+  header_rows: 11
+  header_cols: 21
   expect:
     - date: !!python/object/apply:datetime.date [2017, 10, 28]
       currency: USD

tests/test_importers.py

@@ -1,8 +1,11 @@
+import csv
 import datetime
 import decimal
+import io
 import importlib
 import itertools
 import pathlib
+import shutil
 import re
 
 import pytest
@@ -28,6 +31,25 @@ class TestImporters:
         with source_path.open() as source_file:
             assert importer.can_import(source_file)
 
+    @pytest.mark.parametrize('source_path,importer,header_rows,header_cols', [
+        (t['source'], t['importer'], t['header_rows'], t['header_cols'])
+        for t in test_data if t.get('header_rows')
+    ])
+    def test_can_import_squared_csv(self, source_path, importer, header_rows, header_cols):
+        # Sometimes when we munge spreadsheets by hand (e.g., to filter by
+        # project) tools like LibreOffice Calc write a "squared" spreadsheet,
+        # where every row has the same length.  This test ensures the results
+        # are still recognized for import.
+        with io.StringIO() as squared_file:
+            csv_writer = csv.writer(squared_file)
+            with source_path.open() as source_file:
+                for row in itertools.islice(csv.reader(source_file), header_rows):
+                    padding = [None] * (header_cols - len(row))
+                    csv_writer.writerow(row + padding)
+                shutil.copyfileobj(source_file, squared_file)
+            squared_file.seek(0)
+            assert importer.can_import(squared_file)
+
     @pytest.mark.parametrize('source_path,import_class,expect_results', [
         (t['source'], t['importer'], t['expect']) for t in test_data
     ])