fix tox and poetry interaction

The Poetry FAQ[1] gives some options on how tox and poetry can be used
together, since both of them want to do the virtual env managing. Since
we mostly want to use tox as a venv manager and to easily run multiple
linters, and we want to have poetry do the dependency management, the
method of explicitely using `poetry install` seems to be the most
reasonable. This means we don't have to generate a requirements.txt file
or make duplicated listings of our dependencies in tox.ini.

[1]: https://python-poetry.org/docs/master/faq/#is-tox-supported

1 files changed, 21 insertions, 22 deletions

diff --git a/tox.ini b/tox.ini
index 88bcef6..3c39ed3 100644
--- a/tox.ini
+++ b/tox.ini
@@ -7,59 +7,58 @@ per-file-ignores =
 
 [tox]
 envlist = python,pylint,pylint-tests,flake8,mypy,black
+# This can be removed in tox 4 as it will be the default:
 isolated_build = true
 
 [testenv]
-deps =
-    pytest
-    lxml: lxml
-extras = testing
+deps = poetry
+skip_install = true
 passenv =
     TERM
+commands_pre =
+    poetry install -v --with testing
 commands =
     pytest {posargs}
 
 [testenv:pylint]
-deps = pylint
-usedevelop = true
+commands_pre =
+    poetry install -v --with linters
 commands =
     pylint --rcfile=pylint.toml fietsboek
 
 [testenv:pylint-tests]
-deps = pylint
-usedevelop = true
 allowlist_externals = bash
+commands_pre =
+    poetry install -v --with linters,testing
 commands =
     bash -c "pylint --rcfile=pylint.tests.toml tests/**/*.py"
 
 [testenv:flake8]
-deps = flake8
-usedevelop = true
+# This is a bit of a hack since flake8 specifies Python 3.8 as minimum required
+# version, while fietsboek only specifices 3.7. Thus, we manually install
+# flake8 via pip and bypass poetry's locking-
+commands_pre =
+    poetry install -v
+    pip install flake8
 commands =
     flake8 fietsboek
 
 [testenv:sphinx]
-deps = sphinx
-usedevelop = true
 allowlist_externals = make
 changedir={toxinidir}{/}doc
+commands_pre =
+    poetry install -v --with docs
 commands =
     make html
 
 [testenv:mypy]
-deps =
-    mypy
-    types-Markdown
-    types-bleach
-    types-babel
-    types-redis
-    types-requests
-usedevelop = true
+commands_pre =
+    poetry install --with types
 commands =
     mypy fietsboek
 
 [testenv:black]
 deps = black
-usedevelop = true
+commands_pre =
 commands =
-    black --check fietsboek
+    black --diff --check fietsboek