diff --git a/pyproject.toml b/pyproject.toml
index 4a2b834..eb764a1 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -31,7 +31,7 @@ dependencies = [
 
 
 [project.optional-dependencies]
-tests = ["pytest"]
+tests = ["pytest", "pytest-cov"]
 docs = [
     "sphinx==4.5.0",
     "sphinx-book-theme==0.3.3",