diff --git a/.coveragerc b/.coveragerc
new file mode 100644
index 0000000..2ae1a3a
--- /dev/null
+++ b/.coveragerc
@@ -0,0 +1,14 @@
+[run]
+include =
+  aprsd/*
+  tests/*
+  */lib/python*/site-packages/aprsd/*
+  */pypy*/site-packages/aprsd/*
+  *\Lib\site-packages\aprsd\*
+branch = 1
+
+[paths]
+source = aprsd/
+  */lib/python*/site-packages/aprsd/
+  */pypy*/site-packages/aprsd/
+  *\Lib\site-packages\aprsd\
diff --git a/tox.ini b/tox.ini
index f2d935a..dc48f07 100644
--- a/tox.ini
+++ b/tox.ini
@@ -10,17 +10,27 @@ envlist = pre-commit,pep8,fmt-check,py{36,37,38}
 isolated_build = true
 
 [testenv]
-setenv = VIRTUAL_ENV={envdir}
+setenv = _PYTEST_SETUP_SKIP_APRSD_DEP=1
+         coverage: _APRSD_TOX_CMD=coverage run -m pytest
 usedevelop = True
 install_command = pip install {opts} {packages}
-deps = -r{toxinidir}/requirements.txt
+extras = tests
+deps = coverage: coverage
+       -r{toxinidir}/requirements.txt
        -r{toxinidir}/dev-requirements.txt
+       pytestmain: git+https://github.com/pytest-dev/pytest.git@main
 commands =
-    # Use -bb to enable BytesWarnings as error to catch str/bytes misuse.
-    # Use -Werror to treat warnings as errors.
-#    {envpython} -bb -Werror -m pytest \
-#        --cov="{envsitepackagesdir}/aprsd" --cov-report=html --cov-report=term {posargs}
-    {envpython} -bb -m pytest {posargs}
+    {env:_APRSD_TOX_CMD:pytest} {posargs}
+    coverage: coverage report -m
+    coverage: coverage xml
+
+[pytest]
+minversion=2.0
+testpaths = tests
+#--pyargs --doctest-modules --ignore=.tox
+addopts=-r a
+filterwarnings =
+  error
 
 [testenv:docs]
 skip_install = true
@@ -94,13 +104,13 @@ commands =
 
 [testenv:type-check]
 skip_install = true
-deps =
-    -r{toxinidir}/requirements.txt
+deps = -r{toxinidir}/requirements.txt
     -r{toxinidir}/dev-requirements.txt
 commands =
     mypy aprsd
 
 [testenv:pre-commit]
 skip_install = true
+basepython = python3
 deps = pre-commit
 commands = pre-commit run --all-files --show-diff-on-failure