tests: print stdout in error msg for no_stdout()
Fix a bug in which the error message displayed when using
`CmdResult::no_stdout()` was incorrectly showing stderr when it should
have been showing stdout.
@@ -221,7 +221,7 @@ impl CmdResult {
assert!(
self.stdout.is_empty(),
"Expected stdout to be empty, but it's:\n{}",
- self.stderr_str()
+ self.stdout_str()
);
self
}
