black in csv and django appendices

appendix_csvs.asciidoc

@@ -26,36 +26,32 @@ Here's an E2E test to show you how the CSVs flow in and out:
 ====
 [source,python]
 ----
-def test_cli_app_reads_csvs_with_batches_and_orders_and_outputs_allocations(
-        make_csv
-):
-    sku1, sku2 = random_ref('s1'), random_ref('s2')
-    batch1, batch2, batch3 = random_ref('b1'), random_ref('b2'), random_ref('b3')
-    order_ref = random_ref('o')
-    make_csv('batches.csv', [
-        ['ref', 'sku', 'qty', 'eta'],
-        [batch1, sku1, 100, ''],
-        [batch2, sku2, 100, '2011-01-01'],
-        [batch3, sku2, 100, '2011-01-02'],
+def test_cli_app_reads_csvs_with_batches_and_orders_and_outputs_allocations(make_csv):
+    sku1, sku2 = random_ref("s1"), random_ref("s2")
+    batch1, batch2, batch3 = random_ref("b1"), random_ref("b2"), random_ref("b3")
+    order_ref = random_ref("o")
+    make_csv("batches.csv", [
+        ["ref", "sku", "qty", "eta"],
+        [batch1, sku1, 100, ""],
+        [batch2, sku2, 100, "2011-01-01"],
+        [batch3, sku2, 100, "2011-01-02"],
     ])
-    orders_csv = make_csv('orders.csv', [
-        ['orderid', 'sku', 'qty'],
+    orders_csv = make_csv("orders.csv", [
+        ["orderid", "sku", "qty"],
         [order_ref, sku1, 3],
         [order_ref, sku2, 12],
     ])
 
     run_cli_script(orders_csv.parent)
 
-    expected_output_csv = orders_csv.parent / 'allocations.csv'
+    expected_output_csv = orders_csv.parent / "allocations.csv"
     with open(expected_output_csv) as f:
         rows = list(csv.reader(f))
     assert rows == [
-        ['orderid', 'sku', 'qty', 'batchref'],
-        [order_ref, sku1, '3', batch1],
-        [order_ref, sku2, '12', batch2],
+        ["orderid", "sku", "qty", "batchref"],
+        [order_ref, sku1, "3", batch1],
+        [order_ref, sku2, "12", batch2],
     ]
-
-
 ----
 ====
 
@@ -75,48 +71,46 @@ import sys
 from datetime import datetime
 from pathlib import Path
 
-from allocation import model
+from allocation.domain import model
+
 
 def load_batches(batches_path):
     batches = []
     with batches_path.open() as inf:
         reader = csv.DictReader(inf)
         for row in reader:
-            if row['eta']:
-                eta = datetime.strptime(row['eta'], '%Y-%m-%d').date()
+            if row["eta"]:
+                eta = datetime.strptime(row["eta"], "%Y-%m-%d").date()
             else:
                 eta = None
-            batches.append(model.Batch(
-                ref=row['ref'],
-                sku=row['sku'],
-                qty=int(row['qty']),
-                eta=eta
-            ))
+            batches.append(
+                model.Batch(
+                    ref=row["ref"], sku=row["sku"], qty=int(row["qty"]), eta=eta
+                )
+            )
     return batches
 
 
-
 def main(folder):
-    batches_path = Path(folder) / 'batches.csv'
-    orders_path = Path(folder) / 'orders.csv'
-    allocations_path = Path(folder) / 'allocations.csv'
+    batches_path = Path(folder) / "batches.csv"
+    orders_path = Path(folder) / "orders.csv"
+    allocations_path = Path(folder) / "allocations.csv"
 
     batches = load_batches(batches_path)
 
-    with orders_path.open() as inf, allocations_path.open('w') as outf:
+    with orders_path.open() as inf, allocations_path.open("w") as outf:
         reader = csv.DictReader(inf)
         writer = csv.writer(outf)
-        writer.writerow(['orderid', 'sku', 'batchref'])
+        writer.writerow(["orderid", "sku", "batchref"])
         for row in reader:
-            orderid, sku = row['orderid'], row['sku']
-            qty = int(row['qty'])
+            orderid, sku = row["orderid"], row["sku"]
+            qty = int(row["qty"])
             line = model.OrderLine(orderid, sku, qty)
             batchref = model.allocate(line, batches)
             writer.writerow([line.orderid, line.sku, batchref])
 
 
-
-if __name__ == '__main__':
+if __name__ == "__main__":
     main(sys.argv[1])
 ----
 ====
@@ -135,35 +129,33 @@ things:
 ====
 [source,python]
 ----
-def test_cli_app_also_reads_existing_allocations_and_can_append_to_them(
-        make_csv
-):
-    sku = random_ref('s')
-    batch1, batch2 = random_ref('b1'), random_ref('b2')
-    old_order, new_order = random_ref('o1'), random_ref('o2')
-    make_csv('batches.csv', [
-        ['ref', 'sku', 'qty', 'eta'],
-        [batch1, sku, 10, '2011-01-01'],
-        [batch2, sku, 10, '2011-01-02'],
+def test_cli_app_also_reads_existing_allocations_and_can_append_to_them(make_csv):
+    sku = random_ref("s")
+    batch1, batch2 = random_ref("b1"), random_ref("b2")
+    old_order, new_order = random_ref("o1"), random_ref("o2")
+    make_csv("batches.csv", [
+        ["ref", "sku", "qty", "eta"],
+        [batch1, sku, 10, "2011-01-01"],
+        [batch2, sku, 10, "2011-01-02"],
     ])
-    make_csv('allocations.csv', [
-        ['orderid', 'sku', 'qty', 'batchref'],
+    make_csv("allocations.csv", [
+        ["orderid", "sku", "qty", "batchref"],
         [old_order, sku, 10, batch1],
     ])
-    orders_csv = make_csv('orders.csv', [
-        ['orderid', 'sku', 'qty'],
+    orders_csv = make_csv("orders.csv", [
+        ["orderid", "sku", "qty"],
         [new_order, sku, 7],
     ])
 
     run_cli_script(orders_csv.parent)
 
-    expected_output_csv = orders_csv.parent / 'allocations.csv'
+    expected_output_csv = orders_csv.parent / "allocations.csv"
     with open(expected_output_csv) as f:
         rows = list(csv.reader(f))
     assert rows == [
-        ['orderid', 'sku', 'qty', 'batchref'],
-        [old_order, sku, '10', batch1],
-        [new_order, sku, '7', batch2],
+        ["orderid", "sku", "qty", "batchref"],
+        [old_order, sku, "10", batch1],
+        [new_order, sku, "7", batch2],
     ]
 ----
 ====
@@ -192,10 +184,9 @@ collection of domain objects:
 [source,python]
 ----
 class CsvRepository(repository.AbstractRepository):
-
     def __init__(self, folder):
-        self._batches_path = Path(folder) / 'batches.csv'
-        self._allocations_path = Path(folder) / 'allocations.csv'
+        self._batches_path = Path(folder) / "batches.csv"
+        self._allocations_path = Path(folder) / "allocations.csv"
         self._batches = {}  # type: Dict[str, model.Batch]
         self._load()
 
@@ -209,22 +200,20 @@ class CsvRepository(repository.AbstractRepository):
         with self._batches_path.open() as f:
             reader = csv.DictReader(f)
             for row in reader:
-                ref, sku = row['ref'], row['sku']
-                qty = int(row['qty'])
-                if row['eta']:
-                    eta = datetime.strptime(row['eta'], '%Y-%m-%d').date()
+                ref, sku = row["ref"], row["sku"]
+                qty = int(row["qty"])
+                if row["eta"]:
+                    eta = datetime.strptime(row["eta"], "%Y-%m-%d").date()
                 else:
                     eta = None
-                self._batches[ref] = model.Batch(
-                    ref=ref, sku=sku, qty=qty, eta=eta
-                )
+                self._batches[ref] = model.Batch(ref=ref, sku=sku, qty=qty, eta=eta)
         if self._allocations_path.exists() is False:
             return
         with self._allocations_path.open() as f:
             reader = csv.DictReader(f)
             for row in reader:
-                batchref, orderid, sku = row['batchref'], row['orderid'], row['sku']
-                qty = int(row['qty'])
+                batchref, orderid, sku = row["batchref"], row["orderid"], row["sku"]
+                qty = int(row["qty"])
                 line = model.OrderLine(orderid, sku, qty)
                 batch = self._batches[batchref]
                 batch._allocations.add(line)
@@ -248,14 +237,13 @@ And here's what a UoW for CSVs would look like:
 [source,python]
 ----
 class CsvUnitOfWork(unit_of_work.AbstractUnitOfWork):
-
     def __init__(self, folder):
         self.batches = CsvRepository(folder)
 
     def commit(self):
-        with self.batches._allocations_path.open('w') as f:
+        with self.batches._allocations_path.open("w") as f:
             writer = csv.writer(f)
-            writer.writerow(['orderid', 'sku', 'qty', 'batchref'])
+            writer.writerow(["orderid", "sku", "qty", "batchref"])
             for batch in self.batches.list():
                 for line in batch._allocations:
                     writer.writerow(
@@ -280,13 +268,13 @@ _existing_ service layer:
 [source,python]
 ----
 def main(folder):
-    orders_path = Path(folder) / 'orders.csv'
+    orders_path = Path(folder) / "orders.csv"
     uow = csv_uow.CsvUnitOfWork(folder)
     with orders_path.open() as f:
         reader = csv.DictReader(f)
         for row in reader:
-            orderid, sku = row['orderid'], row['sku']
-            qty = int(row['qty'])
+            orderid, sku = row["orderid"], row["sku"]
+            qty = int(row["qty"])
             services.allocate(orderid, sku, qty, uow)
 ----
 ====

appendix_django.asciidoc

@@ -139,7 +139,6 @@ Here's how the actual repository ends up looking:
 [source,python]
 ----
 class DjangoRepository(AbstractRepository):
-
     def add(self, batch):
         super().add(batch)
         self.update(batch)
@@ -148,9 +147,11 @@ class DjangoRepository(AbstractRepository):
         django_models.Batch.update_from_domain(batch)
 
     def _get(self, reference):
-        return django_models.Batch.objects.filter(
-            reference=reference
-        ).first().to_domain()
+        return (
+            django_models.Batch.objects.filter(reference=reference)
+            .first()
+            .to_domain()
+        )
 
     def list(self):
         return [b.to_domain() for b in django_models.Batch.objects.all()]
@@ -179,6 +180,7 @@ Those custom methods look something like this:
 from django.db import models
 from allocation.domain import model as domain_model
 
+
 class Batch(models.Model):
     reference = models.CharField(max_length=255)
     sku = models.CharField(max_length=255)
@@ -250,6 +252,7 @@ The tests don't change too much:
 def insert_batch(ref, sku, qty, eta):  #<1>
     django_models.Batch.objects.create(reference=ref, sku=sku, qty=qty, eta=eta)
 
+
 def get_allocated_batch_ref(orderid, sku):  #<1>
     return django_models.Allocation.objects.get(
         line__orderid=orderid, line__sku=sku
@@ -258,17 +261,17 @@ def get_allocated_batch_ref(orderid, sku):  #<1>
 
 @pytest.mark.django_db(transaction=True)
 def test_uow_can_retrieve_a_batch_and_allocate_to_it():
-    insert_batch('batch1', 'HIPSTER-WORKBENCH', 100, None)
+    insert_batch("batch1", "HIPSTER-WORKBENCH", 100, None)
 
     uow = unit_of_work.DjangoUnitOfWork()
     with uow:
-        batch = uow.batches.get(reference='batch1')
-        line = model.OrderLine('o1', 'HIPSTER-WORKBENCH', 10)
+        batch = uow.batches.get(reference="batch1")
+        line = model.OrderLine("o1", "HIPSTER-WORKBENCH", 10)
         batch.allocate(line)
         uow.commit()
 
-    batchref = get_allocated_batch_ref('o1', 'HIPSTER-WORKBENCH')
-    assert batchref == 'batch1'
+    batchref = get_allocated_batch_ref("o1", "HIPSTER-WORKBENCH")
+    assert batchref == "batch1"
 
 
 @pytest.mark.django_db(transaction=True)  #<2>
@@ -301,7 +304,6 @@ would work:
 [source,python]
 ----
 class DjangoUnitOfWork(AbstractUnitOfWork):
-
     def __enter__(self):
         self.batches = repository.DjangoRepository()
         transaction.set_autocommit(False)  #<1>
@@ -353,35 +355,37 @@ thin wrapper around our service layer (which didn't change at all, by the way):
 ====
 [source,python]
 ----
-os.environ['DJANGO_SETTINGS_MODULE'] = 'djangoproject.django_project.settings'
+os.environ["DJANGO_SETTINGS_MODULE"] = "djangoproject.django_project.settings"
 django.setup()
 
+
 @csrf_exempt
 def add_batch(request):
     data = json.loads(request.body)
-    eta = data['eta']
+    eta = data["eta"]
     if eta is not None:
         eta = datetime.fromisoformat(eta).date()
     services.add_batch(
-        data['ref'], data['sku'], data['qty'], eta,
+        data["ref"], data["sku"], data["qty"], eta,
         unit_of_work.DjangoUnitOfWork(),
     )
-    return HttpResponse('OK', status=201)
+    return HttpResponse("OK", status=201)
+
 
 @csrf_exempt
 def allocate(request):
     data = json.loads(request.body)
     try:
         batchref = services.allocate(
-            data['orderid'],
-            data['sku'],
-            data['qty'],
+            data["orderid"],
+            data["sku"],
+            data["qty"],
             unit_of_work.DjangoUnitOfWork(),
         )
     except (model.OutOfStock, services.InvalidSku) as e:
-        return JsonResponse({'message': str(e)}, status=400)
+        return JsonResponse({"message": str(e)}, status=400)
 
-    return JsonResponse({'batchref': batchref}, status=201)
+    return JsonResponse({"batchref": batchref}, status=201)
 ----
 ====