diff --git a/tox.ini b/tox.ini
index e83adc9..6f808a1 100644
--- a/tox.ini
+++ b/tox.ini
@@ -6,7 +6,11 @@ deps =
     pytest
     pytest-cov
 
-commands = py.test --cov-report=term --cov-report= --cov=price_parser --doctest-modules {posargs:price_parser tests README.rst}
+commands =
+    py.test \
+        --cov-report=term --cov-report= --cov=price_parser \
+        --doctest-modules \
+        {posargs:price_parser tests README.rst}
 
 [testenv:mypy]
 deps =