test: expect signed one-time material uploads

- TestUploadTicket: HMAC under the jz.bm.upload.v1: label, expiry,
  malformed and foreign tickets, single use through the cache
- TestSignedMaterialUploadRefusesBadTickets, TestCreateMaterialUploadNeedsCaller
- TestRoutes, TestBMMCP and TestManageBucketKey expect the upload-url
  route, the uploads route with its two buckets and the upload tool
- compile-only stubs

controllers/api/api.go

@@ -14,6 +14,7 @@ import (
 	chatclasses "git.golem15.com/golem15/sm-chat-plugin/classes"
 	chanclasses "git.golem15.com/golem15/sm-chatchannels-plugin/classes"
 	"git.golem15.com/golem15/summercms/modules/bouncer"
+	"git.golem15.com/golem15/summercms/modules/cooler"
 	"git.golem15.com/golem15/summercms/modules/phrasebook"
 	"git.golem15.com/golem15/summercms/modules/wire"
 	"gocloud.dev/blob"
@@ -66,6 +67,12 @@ type Handlers struct {
 	// ChatBots is whether golem15.chatbots is active, so its is_bot flags
 	// can be read.
 	ChatBots bool
+	// UploadKey returns the key the signed material upload URLs are signed
+	// with (app.key), or nil when none is set: then no URL is issued.
+	UploadKey func() []byte
+	// Cache returns the application cache that holds the issued upload
+	// tickets until they are used, or nil while none is available.
+	Cache func() cooler.Cache
 }
 
 func (h *Handlers) now() time.Time {