tests: add coverage tests with tox

Author: azmeuk

pyproject.toml

@@ -0,0 +1,12 @@
+[tool.coverage.run]
+branch = true
+source = ["wtforms_sqlalchemy", "tests"]
+
+[tool.coverage.paths]
+source = ["src", "*/site-packages"]
+
+[tool.coverage.report]
+exclude_lines = [
+    "pragma: no cover",
+    "except ImportError:",
+]

tox.ini

@@ -1,13 +1,10 @@
 [tox]
-envlist = py38, py39, py310, py311, py312, style, docs
+envlist = style, py312, py311, py310, py39, py38, coverage, docs
 
 [testenv]
 deps =
-  coverage
   pytest
-setenv =
-  PYTHONPATH = {toxinidir}:{toxinidir}/
-commands = pytest
+commands = pytest {posargs}
 
 [testenv:style]
 deps = pre-commit
@@ -17,3 +14,12 @@ commands = pre-commit run --all-files --show-diff-on-failure
 [testenv:docs]
 deps = -r docs/requirements.txt
 commands = sphinx-build -W -b html -d {envtmpdir}/doctrees docs {envtmpdir}/html
+
+[testenv:coverage]
+deps =
+    pytest
+    coverage
+commands =
+    coverage run -m pytest --tb=short --basetemp={envtmpdir} {posargs}
+    coverage html
+    coverage report