tests: fix object containment violations in the transmogrifier tests

Some objects were not completely rewritten in the tests, which caused object
containment violations.  Fix them by rewriting the object IDs to be in an
appropriate namespace.

CHANGELOG.md

@@ -42,6 +42,10 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - Admin API: changed json structure for saving config settings.
 - RichMedia: parsers and their order are configured in `rich_media` config.
 
+## [1.0.1] - 2019-07-14
+### Security
+- OStatus: fix an object spoofing vulnerability.
+
 ## [1.0.0] - 2019-06-29
 ### Security
 - Mastodon API: Fix display names not being sanitized

test/web/activity_pub/transmogrifier_test.exs

@@ -416,6 +416,7 @@ test "it ensures that as:Public activities make it to their followers collection
         |> Map.put("attributedTo", user.ap_id)
         |> Map.put("to", ["https://www.w3.org/ns/activitystreams#Public"])
         |> Map.put("cc", [])
+        |> Map.put("id", user.ap_id <> "/activities/12345678")
 
       data = Map.put(data, "object", object)
 
@@ -439,6 +440,7 @@ test "it ensures that address fields become lists" do
         |> Map.put("attributedTo", user.ap_id)
         |> Map.put("to", nil)
         |> Map.put("cc", nil)
+        |> Map.put("id", user.ap_id <> "/activities/12345678")
 
       data = Map.put(data, "object", object)