Use latest developer version of Numpy and pytest for Python 3.12

Author: astrofrog

tox.ini

@@ -9,6 +9,9 @@ isolated_build = true
 
 [testenv]
 changedir = .tmp/{envname}
+setenv =
+    # Until a released numpy version is 3.12 compatible, we install the dev wheel
+    py312: PIP_EXTRA_INDEX_URL = https://pypi.anaconda.org/scientific-python-nightly-wheels/simple
 description = run tests
 deps =
     pytestoldest: pytest==4.6.0
@@ -24,6 +27,8 @@ deps =
     pytest73: pytest==7.3.*
     pytest74: pytest==7.4.*
     pytestdev: git+https://github.com/pytest-dev/pytest#egg=pytest
+    py312: git+https://github.com/pytest-dev/pytest#egg=pytest
+    py312: numpy>=0.0.dev0
 extras =
     test
 commands =