diff --git a/setup.cfg b/setup.cfg
index f63239aed..c9664956d 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -39,6 +39,7 @@ install_requires =
   Jinja2 <3.1
 tests_require =
   pytest
+  readthedocs-sphinx-ext
 
 [options.extras_require]
 dev =
diff --git a/tox.ini b/tox.ini
index ad7c6f71d..bd93ce9d0 100644
--- a/tox.ini
+++ b/tox.ini
@@ -8,10 +8,7 @@ envlist =
 setev =
     LANG=C
 deps =
-    .
-    readthedocs-sphinx-ext
-    pytest
-    sphinxcontrib-httpdomain
+    .[test,dev]
     sphinx16: Sphinx>=1.6,<1.7
     sphinx17: Sphinx>=1.7,<1.8
     sphinx18: Sphinx>=1.8,<1.9