Add tox.ini, remove test.sh

The tests can be run now using `tox` against multiple Anki versions;
see instructions in `tox.ini`.

The tests depend on `pytest-anki` that had to be slightly modified
to remove the upper constraint on Anki version, as well as
to remove a few dependencies that are not essential to using it.

test.sh

@@ -1,2 +0,0 @@
-#!/usr/bin/bash
-python -m unittest discover -v tests

tox.ini

@@ -0,0 +1,76 @@
+# For testing, you will need:
+#   * PyQt5 dev tools
+#   * tox
+#   * X virtual framebuffer--to test without GUI
+#
+# Install these by running:
+#   $ sudo apt install pyqt5-dev-tools xvfb
+#   $ python3 -m pip install --user --upgrade tox
+#
+# Then, to run tests against multiple anki versions:
+#   $ tox
+#
+# To run tests slightly less safely, but faster:
+#   $ tox -- --no-tear-down-profile-after-each-test
+#
+# To run tests more safely, but *much* slower:
+#   $ tox -- --forked
+
+# Test tool cheat sheet:
+#   * Test several environments in parallel:
+#       $ tox -p auto
+#
+#   * To activate one of the test environments:
+#       $ source .tox/py38-anki49/bin/activate
+#
+#   * Stop on first failure:
+#       $ xvfb-run python -m pytest -x
+#
+#   * See stdout/stderr (doesn't work with --forked!):
+#       $ xvfb-run python -m pytest -s
+#
+#   * Run some specific tests:
+#       $ xvfb-run python -m pytest -k "test_cards.py or test_guiBrowse"
+#
+#   * To run with visible GUI in WSL2
+#     (Make sure to disable access control in your X server, such as VcXsrv):
+#       $ DISPLAY=$(ip route list default | awk '{print $3}'):0 python -m pytest
+#
+#   * Environmental variables of interest:
+#       LIBGL_ALWAYS_INDIRECT=1
+#       QTWEBENGINE_CHROMIUM_FLAGS="--disable-gpu"
+#       QT_DEBUG_PLUGINS=1
+#       ANKIDEV=true
+
+[tox]
+minversion = 3.24
+skipsdist = true
+skip_install = true
+envlist = py38-anki{45,46,47,48,49}
+
+[testenv]
+commands =
+    xvfb-run python -m pytest {posargs}
+setenv =
+    HOME={envdir}/home
+allowlist_externals =
+    xvfb-run
+deps =
+    pytest==7.1.1
+    pytest-forked==1.4.0
+    pytest-anki @ git+https://github.com/oakkitten/pytest-anki.git@17d19043
+
+    anki45: anki==2.1.45
+    anki45: aqt==2.1.45
+
+    anki46: anki==2.1.46
+    anki46: aqt==2.1.46
+
+    anki47: anki==2.1.47
+    anki47: aqt==2.1.47
+
+    anki48: anki==2.1.48
+    anki48: aqt==2.1.48
+
+    anki49: anki==2.1.49
+    anki49: aqt==2.1.49