fix listings for di and bootstrap chapters

appendix_bootstrap.asciidoc

@@ -81,12 +81,14 @@ Here's what a bootstrap script could look like:
 def bootstrap(
         start_orm=orm.start_mappers,
         session_factory=DEFAULT_SESSION_FACTORY,
-        send_mail=email.send,
+        notifications=None,
         publish=redis_pubsub.publish,
 ):
     start_orm()
     uow = unit_of_work.SqlAlchemyUnitOfWork(session_factory=session_factory)
-    bus = messagebus.MessageBus(uow=uow, send_mail=send_mail, publish=publish)
+    if notifications is None:
+        notifications = EmailNotifications(smtp_host=EMAIL_HOST, port=EMAIL_PORT)
+    bus = messagebus.MessageBus(uow=uow, notifications=notifications, publish=publish)
     return bus
 ----
 ====
@@ -132,7 +134,7 @@ to get a custom messagebus:
 def sqlite_bus(in_memory_sqlite_db):
     yield bootstrap.bootstrap(
         session_factory=sessionmaker(bind=in_memory_sqlite_db),
-        send_mail=mock.Mock(),
+        notifications=mock.Mock(),
         publish=mock.Mock(),
     )
     clear_mappers()
@@ -180,7 +182,8 @@ One fix is to split the "pub" from the "sub":
 
 image::images/appendix_bootstrap_dependency_graph_2.png["Dependency graph with bootstrap script and no circular deps"]
 
-Now we have what our esteemed tech reviewer David Seddon would call a "rocky road architecture": all the dependencies
-flow in one direction.
+Now we have what our esteemed tech reviewer David Seddon would call a "rocky
+road architecture": all the dependencies flow in one direction.
 
 TODO: alternative fix by making an abstract redis thingie?  
+

chapter_10_dependency_injection.asciidoc

@@ -156,6 +156,7 @@ we have an (explicit) dependency on an abstraction:
 .The explicit dependency is more abstract (src/allocation/handlers.py)
 ====
 [source,python]
+[role="non-head"]
 ----
 def send_out_of_stock_notification(
         event: events.OutOfStock, send_mail: Callable,
@@ -185,6 +186,7 @@ Here's one way to do it:
 .MessageBus as a class (src/allocation/messagebus.py)
 ====
 [source,python]
+[role="non-head"]
 ----
 class MessageBus:  #<1>
 
@@ -258,7 +260,7 @@ What else changes in the bus?
 Here's the core of our dependency injection approach then.  As you'll see
 there's not much to it:
 
-[[messagebus_does_DI]]
+[[messagebus_does_DI0]]
 .Dependency injection in 3 lines of code (src/allocation/messagebus.py)
 ====
 [source,python]
@@ -326,6 +328,7 @@ dependencies we want to use:
 .Flask initialises a bus with the production dependencies (src/allocation/flask_app.py)
 ====
 [source,python]
+[role="non-head"]
 ----
 from allocation import (
     commands, email, exceptions, messagebus, orm, redis_pubsub, unit_of_work,
@@ -348,6 +351,7 @@ bus = messagebus.MessageBus(
 .So does redis (src/allocation/redis_pubsub.py)
 ====
 [source,python]
+[role="non-head"]
 ----
 def get_bus():  #<1>
     return messagebus.MessageBus(
@@ -378,10 +382,11 @@ def handle_change_batch_quantity(m, bus: messagebus.MessageBus):
 === Initialising DI In Our Tests
 
 
-[[totally_reimplement_bootstrap]]
+[[fakebus]]
 .Handler tests just do their own bootstrap (tests/unit/test_handlers.py)
 ====
 [source,python]
+[role="non-head"]
 ----
 class FakeBus(messagebus.MessageBus):
     def __init__(self):
@@ -409,14 +414,15 @@ class TestAddBatch:
 
 We've got two types of dependency:
 
-[[two_types_of_dependency]]
-.Two types of dependency
+[[messagebus_does_DI]]
+.Two types of dependency (src/allocation/messagebus.py)
 ====
 [source,python]
+[role="non-head"]
 ----
-        uow: unit_of_work.AbstractUnitOfWork,  #<1>
-        send_mail: Callable,  #<2>
-        publish: Callable,  #<2>
+            uow: unit_of_work.AbstractUnitOfWork,  #<1>
+            send_mail: Callable,  #<2>
+            publish: Callable,  #<2>
 ----
 ====
 
@@ -457,6 +463,7 @@ class Notifications(abc.ABC):
     def send(self, destination, message):
         raise NotImplementedError
 
+...
 
 class EmailNotifications(Notifications):
 
@@ -526,7 +533,7 @@ class FakeBus(messagebus.MessageBus):
 we can use it in our tests:
 
 [[test_with_fake_notifs]]
-.Tests change slightly (test/unit/tests_handlers.py)
+.Tests change slightly (tests/unit/test_handlers.py)
 ====
 [source,python]
 ----