diff --git a/pyproject.toml b/pyproject.toml
index 0a562cbb..078f5ef9 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -102,6 +102,7 @@ msgspec = [
 addopts = "-l --benchmark-sort=fullname --benchmark-warmup=true --benchmark-warmup-iterations=5  --benchmark-group-by=fullname"
 
 [tool.coverage.run]
+branch = true
 parallel = true
 source_pkgs = ["cattrs", "tests"]