diff --git a/pyproject.toml b/pyproject.toml
index 896108f..6a62f46 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -77,7 +77,7 @@ dev-pytest = [
   "frequenz-repo-config[extra-lint-examples] == 0.17.0",
   "pytest-mock == 3.14.0",
   "pytest-asyncio == 1.3.0",
-  "async-solipsism == 0.8",
+  "async-solipsism == 0.9",
 ]
 dev = [
   "frequenz-resampling[dev-mkdocs,dev-flake8,dev-formatting,dev-mkdocs,dev-mypy,dev-noxfile,dev-pylint,dev-pytest]",