diff --git a/tox.ini b/tox.ini
index bde33c9..7fda9f0 100644
--- a/tox.ini
+++ b/tox.ini
@@ -10,7 +10,7 @@ isolated_build = true
 [testenv]
 changedir = .tmp/{envname}
 setenv =
-    devdeps: PIP_EXTRA_INDEX_URL = https://pypi.anaconda.org/astropy/simple https://pypi.anaconda.org/scientific-python-nightly-wheels/simple
+    devdeps: PIP_EXTRA_INDEX_URL = https://pypi.anaconda.org/astropy/simple https://pypi.anaconda.org/liberfa/simple https://pypi.anaconda.org/scientific-python-nightly-wheels/simple
 description = run tests
 deps =
     pytestoldest: pytest==4.6.0
@@ -28,6 +28,7 @@ deps =
     devdeps: git+https://github.com/pytest-dev/pytest#egg=pytest
     devdeps: numpy>=0.0.dev0
     devdeps: pandas>=0.0.dev0
+    devdeps: pyerfa>=0.0.dev0
     devdeps: astropy>=0.0.dev0
 extras =
     test