From 006981320d20466f3f88a63932a725f66adcea51 Mon Sep 17 00:00:00 2001
From: Sebastian Wagner <sewagner@redhat.com>
Date: Tue, 16 Nov 2021 14:08:56 +0100
Subject: [PATCH] teuthology/suite/matrix.py: Add item to assert msg

Give folks at least some hint about where things might
be broken:

```
AssertionError: Sum requires non-empty _submats: 0-distro
```

Signed-off-by: Sebastian Wagner <sewagner@redhat.com>
---
 teuthology/suite/matrix.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/teuthology/suite/matrix.py b/teuthology/suite/matrix.py
index 8938fe7d86..055c448523 100644
--- a/teuthology/suite/matrix.py
+++ b/teuthology/suite/matrix.py
@@ -248,7 +248,7 @@ class Sum(Matrix):
     """
     def __init__(self, item, _submats):
         assert len(_submats) > 0, \
-            "Sum requires non-empty _submats"
+            f"Sum requires non-empty _submats: {item}"
         self.item = item
 
         self._pseudo_size = lcml((i.size() for i in _submats)) * len(_submats)
-- 
2.39.5