refactor: Improved test assertions in the app module

Cargo.lock

@@ -135,6 +135,12 @@ dependencies = [
  "wait-timeout",
 ]
 
+[[package]]
+name = "assertables"
+version = "9.8.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "59051ec02907378a67b0ba1b8631121f5388c8dbbb3cec8c749d8f93c2c3c211"
+
 [[package]]
 name = "async-trait"
 version = "0.1.89"
@@ -1375,6 +1381,7 @@ version = "0.6.1"
 dependencies = [
  "anyhow",
  "assert_cmd",
+ "assertables",
  "async-trait",
  "backtrace",
  "bimap",