diff --git a/pyproject.toml b/pyproject.toml
index 08510be..cab902a 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -21,3 +21,8 @@ diff-edit = "diff_edit:main"
 
 [project.urls]
 Homepage = "https://github.com/ahamilton/diff-edit"
+
+[dependency-groups]
+dev = [
+    "pytest>=9.1.1",
+]