diff --git a/tox.ini b/tox.ini
new file mode 100644
index 0000000..0981c97
--- /dev/null
+++ b/tox.ini
@@ -0,0 +1,21 @@
+[tox]
+isolated_build = True
+envlist = py37,py38,py39
+
+[testenv]
+deps =
+    black
+    coverage
+    flake8
+    mccabe
+    mypy
+    pylint
+    pytest
+commands =
+    black warren
+    flake8 warren
+    pylint warren
+    mypy warren
+    coverage erase
+    coverage run --include=warren/* -m pytest -ra
+    coverage report -m