Add integration and more unit tests

- Add integration test for serving cert auto-generation and rotation
- Add unit test for `WithInitialEvent` of the cert manager controller
- Move UpdateAPIService() into the `apicerts` package, since that is
  the only user of the function.

internal/testutil/observable_with_informer_option.go

@@ -8,23 +8,24 @@ package testutil
 import "github.com/suzerain-io/controller-go"
 
 type ObservableWithInformerOption struct {
-	InformerToFilterMap map[controller.InformerGetter]controller.Filter
+	informerToFilterMap map[controller.InformerGetter]controller.Filter
 }
 
 func NewObservableWithInformerOption() *ObservableWithInformerOption {
 	return &ObservableWithInformerOption{
-		InformerToFilterMap: make(map[controller.InformerGetter]controller.Filter),
+		informerToFilterMap: make(map[controller.InformerGetter]controller.Filter),
 	}
 }
 
 func (i *ObservableWithInformerOption) WithInformer(
 	getter controller.InformerGetter,
 	filter controller.Filter,
-	opt controller.InformerOption) controller.Option {
-	i.InformerToFilterMap[getter] = filter
+	opt controller.InformerOption,
+) controller.Option {
+	i.informerToFilterMap[getter] = filter
 	return controller.WithInformer(getter, filter, opt)
 }
 
 func (i *ObservableWithInformerOption) GetFilterForInformer(getter controller.InformerGetter) controller.Filter {
-	return i.InformerToFilterMap[getter]
+	return i.informerToFilterMap[getter]
 }

internal/testutil/observable_with_initial_event_option.go

@@ -0,0 +1,25 @@
+/*
+Copyright 2020 VMware, Inc.
+SPDX-License-Identifier: Apache-2.0
+*/
+
+package testutil
+
+import "github.com/suzerain-io/controller-go"
+
+type ObservableWithInitialEventOption struct {
+	key controller.Key
+}
+
+func NewObservableWithInitialEventOption() *ObservableWithInitialEventOption {
+	return &ObservableWithInitialEventOption{}
+}
+
+func (i *ObservableWithInitialEventOption) WithInitialEvent(key controller.Key) controller.Option {
+	i.key = key
+	return controller.WithInitialEvent(key)
+}
+
+func (i *ObservableWithInitialEventOption) GetInitialEventKey() controller.Key {
+	return i.key
+}