Add support test maintenance

Signed-off-by: Dmitriy Zayakin <d.zayakin@yadro.com>

src/frostfs_testlib/shell/local_shell.py

@@ -62,7 +62,8 @@ class LocalShell(Shell):
         if options.check and result.return_code != 0:
             raise RuntimeError(
                 f"Command: {command}\nreturn code: {result.return_code}\n"
-                f"Output: {result.stdout}"
+                f"Output: {result.stdout}\n"
+                f"Stderr: {result.stderr}\n"
             )
         return result
 
@@ -94,9 +95,7 @@ class LocalShell(Shell):
                 return_code=exc.returncode,
             )
             raise RuntimeError(
-                f"Command: {command}\nError:\n"
-                f"return code: {exc.returncode}\n"
-                f"output: {exc.output}"
+                f"Command: {command}\nError:\n" f"return code: {exc.returncode}\n" f"output: {exc.output}"
             ) from exc
         except OSError as exc:
             raise RuntimeError(f"Command: {command}\nOutput: {exc.strerror}") from exc