diff --git a/tests/assertions.py b/tests/assertions.py
index 87b9b09ed..549420790 100644
--- a/tests/assertions.py
+++ b/tests/assertions.py
@@ -24,5 +24,6 @@ def assert_unchanged(
 
 def assert_one(seq: abc.Sequence[T]) -> T:
     """assert whether a sequence contains only one element and return it"""
+    __tracebackhide__ = True
     assert (l := len(seq)) == 1, f"Expected one element in sequence, found {l} (sequence: {seq!r})"
     return seq[0]