CI: using nightly wheels for testing

Author: bsipocz

tox.ini

@@ -15,8 +15,9 @@ deps =
     -rsite/requirements.txt
     -rrequirements.txt
 
-    # TODO: be clever and use the nightly wheels instead
-    devdeps: git+https://github.com/numpy/numpy.git#egg=numpy
+    devdeps: pip install -U --pre --only-binary :all: -i https://pypi.anaconda.org/scipy-wheels-nightly/simple numpy
+    devdeps: pip install -U --pre --only-binary :all: -i https://pypi.anaconda.org/scipy-wheels-nightly/simple scipy
+    devdeps: pip install -U --pre --only-binary :all: -i https://pypi.anaconda.org/scipy-wheels-nightly/simple matplotlib
 
     # TODO: add the oldest supported versions of all the dependencies here
     # oldestdeps: numpy==1.18