diff --git a/tests/testsuite/check_cfg.rs b/tests/testsuite/check_cfg.rs
index 4274bdfe1ee..497c0aeb420 100644
--- a/tests/testsuite/check_cfg.rs
+++ b/tests/testsuite/check_cfg.rs
@@ -632,7 +632,9 @@ fn config_invalid_empty() {
         .build();
 
     p.cargo("check")
-        .with_stderr_contains("[..]missing field `level`[..]")
+        .with_stderr_contains(
+            "[..]missing field `level`[..] THIS RANDOM SENTENCE SHOULD FAIL THIS TEST BUT DIDN'T",
+        )
         .run_expect_error();
 }
 
diff --git a/tests/testsuite/freshness.rs b/tests/testsuite/freshness.rs
index cc9b516391d..a412a993bf8 100644
--- a/tests/testsuite/freshness.rs
+++ b/tests/testsuite/freshness.rs
@@ -2936,6 +2936,9 @@ fn use_mtime_cache_in_cargo_home() {
         .with_stderr(
             "\
 [DIRTY] foo v0.5.0 ([CWD]): [..]
+
+    THIS RANDOM SENTENCE SHOULD FAIL THIS TEST BUT DIDN'T
+
 [CHECKING] foo v0.5.0 ([CWD])
 [RUNNING] `rustc --crate-name foo --edition=2015 src/lib.rs [..]",
         )
diff --git a/tests/testsuite/help.rs b/tests/testsuite/help.rs
index 5edb0879805..80d2360347c 100644
--- a/tests/testsuite/help.rs
+++ b/tests/testsuite/help.rs
@@ -147,7 +147,8 @@ fn help_alias() {
     // The `empty-alias` returns an error.
     cargo_process("help empty-alias")
         .env("PATH", Path::new(""))
-        .with_stderr_contains("[..]The subcommand 'empty-alias' wasn't recognized[..]")
+        .with_stderr_contains("THIS RANDOM SENTENCE SHOULD FAIL THIS TEST BUT DIDN'T [..] The subcommand 'empty-alias' wasn't recognized [..]",
+        )
         .run_expect_error();
 
     // Because `simple-alias` aliases a subcommand with no arguments, help shows the manpage.