diff --git a/pyproject.toml b/pyproject.toml
index 0513f86..916094e 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -30,6 +30,9 @@ bash_kernel = "^0.7.2"
 jupyter = "^1.0.0"
 pandoc = "^2.0.1"
 pytest = "^6.2.5"
+pytest-icdiff = "^0.5"
+pytest-instafail = "^0.4.2"
+pytest-cov = "^3.0.0"
 
 [build-system]
 requires = ["poetry-core>=1.0.0"]