Check the stderr for publish_allowed

Author: 0xPoe

tests/testsuite/cargo_features.rs

@@ -633,6 +633,20 @@ fn publish_allowed() {
     p.cargo("publish")
         .replace_crates_io(registry.index_url())
         .masquerade_as_nightly_cargo(&["test-dummy-unstable"])
+        .with_stderr(
+            "\
+[UPDATING] crates.io index
+[WARNING] [..]
+[..]
+[PACKAGING] a v0.0.1 [..]
+[VERIFYING] a v0.0.1 [..]
+[COMPILING] a v0.0.1 [..]
+[FINISHED] [..]
+[PACKAGED] [..]
+[UPLOADING] a v0.0.1 [..]
+[UPDATING] crates.io index
+",
+        )
         .run();
 }