Install assert-json-diff

Cargo.lock

@@ -230,6 +230,16 @@ version = "0.10.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9a1bb320f97e6edf9f756bf015900038e43c7700e059688e5724a928c8f3b8d5"
 
+[[package]]
+name = "assert-json-diff"
+version = "2.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "50f1c3703dd33532d7f0ca049168930e9099ecac238e23cf932f3a69c42f06da"
+dependencies = [
+ "serde 1.0.133",
+ "serde_json",
+]
+
 [[package]]
 name = "async-trait"
 version = "0.1.52"
@@ -3218,6 +3228,7 @@ dependencies = [
  "activitypub",
  "activitystreams",
  "ammonia",
+ "assert-json-diff",
  "bcrypt",
  "chrono",
  "diesel",