Linting in tox.ini: use variable for target dirs

Instead of providing a target directory for linting by each of the
tools use one variable which will be the source of truth about which
directories do we lint.

Signed-off-by: Martin Vrachev <[email protected]>

Author: MVrachev

pyproject.toml

@@ -76,12 +76,6 @@ strict_equality = "True"
 disallow_untyped_defs = "True"
 disallow_untyped_calls = "True"
 show_error_codes = "True"
-files = [
-  "tuf/api/",
-  "tuf/ngclient",
-  "tuf/exceptions.py",
-  "examples/",
-]
 
 [[tool.mypy.overrides]]
 module = [

tox.ini

@@ -38,17 +38,18 @@ commands =
 
 [testenv:lint]
 changedir = {toxinidir}
+lint_dirs = tuf/api tuf/ngclient examples
 commands =
     # Use different configs for new (tuf/api/*) and legacy code
-    black --check --diff tuf/api tuf/ngclient examples
-    isort --check --diff tuf/api tuf/ngclient examples
-    pylint -j 0 tuf/api tuf/ngclient --rcfile=pyproject.toml examples
+    black --check --diff {[testenv:lint]lint_dirs}
+    isort --check --diff {[testenv:lint]lint_dirs}
+    pylint -j 0 --rcfile=pyproject.toml {[testenv:lint]lint_dirs}
 
     # NOTE: Contrary to what the pylint docs suggest, ignoring full paths does
     # work, unfortunately each subdirectory has to be ignored explicitly.
     pylint -j 0 tuf --ignore=tuf/api,tuf/api/serialization,tuf/ngclient,tuf/ngclient/_internal
 
-    mypy
+    mypy {[testenv:lint]lint_dirs} tuf/exceptions.py
 
     bandit -r tuf