Import tasks via CSV (#51)

* Bare start on CSV support

* Move core of CSV importer to operations

* More validations, break out validation function

* Validate dates and TaskList; convert errors to list of dictionaries

* Finish upsert code, and documentation

* Print msgs from the mgmt command, not the operations module

* Handle BOM marks

* Handle both in-memory and local file objects

* Update readme

* Working browser-upload view

* Bail on incorrect headers

* Fix default values and finish example spreadsheet

* Change column order, update docs

* Update index.md for RTD

* First round of responses to PR feedback

* Restore independent summaries/errors/upserts properties

* PR responses

* Split off reusable date validator into separate function

* Fix URLs append

* General test suite for CSV importer

todo/tests/test_import.py

@@ -0,0 +1,76 @@
+import datetime
+from pathlib import Path
+
+import pytest
+from django.contrib.auth import get_user_model
+
+from todo.models import Task, TaskList
+from todo.operations.csv_importer import CSVImporter
+
+
+"""
+Exercise the "Import CSV" feature, which shares a functional module that serves
+both the `import_csv` management command and the "Import CSV" web interface.
+"""
+
+
+@pytest.mark.django_db
+@pytest.fixture
+def import_setup(todo_setup):
+    app_path = Path(__file__).resolve().parent.parent
+    filepath = Path(app_path, "tests/data/csv_import_data.csv")
+    with filepath.open(mode="r", encoding="utf-8-sig") as fileobj:
+        importer = CSVImporter()
+        results = importer.upsert(fileobj, as_string_obj=True)
+        assert results
+    return {"results": results}
+
+
+@pytest.mark.django_db
+def test_setup(todo_setup):
+    """Confirm what we should have from conftest, prior to importing CSV."""
+    assert TaskList.objects.all().count() == 2
+    assert Task.objects.all().count() == 6
+
+
+@pytest.mark.django_db
+def test_import(import_setup):
+    """Confirm that importing the CSV gave us two more rows (one should have been skipped)"""
+    assert Task.objects.all().count() == 8  # 2 out of 3 rows should have imported; one was an error
+
+
+@pytest.mark.django_db
+def test_report(import_setup):
+    """Confirm that importing the CSV returned expected report messaging."""
+
+    results = import_setup["results"]
+
+    assert "Processed 3 CSV rows" in results["summaries"]
+    assert "Upserted 2 rows" in results["summaries"]
+    assert "Skipped 1 rows" in results["summaries"]
+
+    assert isinstance(results["errors"], list)
+    assert len(results["errors"]) == 1
+    assert (
+        results["errors"][0].get(3)[0]
+        == "Could not convert Created Date 2015-06-248 to valid date instance"
+    )
+
+    assert (
+        'Upserted task 7: "Make dinner" in list "Zip" (group "Workgroup One")' in results["upserts"]
+    )
+    assert (
+        'Upserted task 8: "Bake bread" in list "Zip" (group "Workgroup One")' in results["upserts"]
+    )
+
+
+@pytest.mark.django_db
+def test_inserted_row(import_setup):
+    """Confirm that one inserted row is exactly right."""
+    task = Task.objects.get(title="Make dinner", task_list__name="Zip")
+    assert task.created_by == get_user_model().objects.get(username="u1")
+    assert task.assigned_to == get_user_model().objects.get(username="u1")
+    assert not task.completed
+    assert task.note == "This is note one"
+    assert task.priority == 3
+    assert task.created_date == datetime.datetime.today().date()