Add tox configuration

Signed-off-by: Alex Forencich <alex@alexforencich.com>

tox.ini

@@ -0,0 +1,33 @@
+# tox configuration
+[tox]
+envlist = py3
+skipsdist = True
+minversion = 3.2.0
+requires = virtualenv >= 16.1
+
+[gh-actions]
+python =
+    3.13: py3
+
+[testenv]
+deps =
+    pytest == 8.3.4
+    pytest-xdist == 3.6.1
+    pytest-split == 0.10.0
+    cocotb == 1.9.2
+    cocotb-bus == 0.2.1
+    cocotb-test == 0.2.6
+    cocotbext-axi == 0.1.24
+    cocotbext-eth == 0.1.22
+    cocotbext-pcie == 0.2.14
+    cocotbext-uart == 0.1.2
+
+commands =
+    pytest {posargs:-n auto --verbose}
+
+# pytest configuration
+[pytest]
+testpaths =
+    tb
+addopts =
+    --import-mode importlib