1 files changed, 27 insertions, 6 deletions
diff --git a/tox.ini b/tox.ini
index 8e8b495292..801e6dea2c 100644
--- a/tox.ini
+++ b/tox.ini
@@ -2,7 +2,6 @@
 envlist = packaging, py35, py36, py37, py38, py39, check_codestyle, check_isort
 
 [base]
-extras = test
 deps =
     python-subunit
     junitxml
@@ -25,10 +24,29 @@ deps =
     # install the "enum34" dependency of cryptography.
     pip>=10
 
+# directories/files we run the linters on
+lint_targets =
+    setup.py
+    synapse
+    tests
+    scripts
+    scripts-dev
+    stubs
+    contrib
+    synctl
+    synmark
+    .buildkite
+    docker
+
+# default settings for all tox environments
 [testenv]
 deps =
     {[base]deps}
-extras = all, test
+extras =
+    # install the optional dependendencies for tox environments without
+    # '-noextras' in their name
+    !noextras: all
+    test
 
 setenv =
     # use a postgres db for tox environments with "-postgres" in the name
@@ -85,6 +103,9 @@ usedevelop=true
 [testenv:py35-old]
 skip_install=True
 deps =
+    # Ensure a version of setuptools that supports Python 3.5 is installed.
+    setuptools < 51.0.0
+
     # Old automat version for Twisted
     Automat == 0.3.0
 
@@ -96,7 +117,7 @@ commands =
     # Make all greater-thans equals so we test the oldest version of our direct
     # dependencies, but make the pyopenssl 17.0, which can work against an
     # OpenSSL 1.1 compiled cryptography (as older ones don't compile on Travis).
-    /bin/sh -c 'python -m synapse.python_dependencies | sed -e "s/>=/==/g" -e "s/psycopg2==2.6//" -e "s/pyopenssl==16.0.0/pyopenssl==17.0.0/" | xargs -d"\n" pip install'
+    /bin/sh -c 'python -m synapse.python_dependencies | sed -e "s/>=/==/g" -e "/psycopg2/d" -e "s/pyopenssl==16.0.0/pyopenssl==17.0.0/" | xargs -d"\n" pip install'
 
     # Install Synapse itself. This won't update any libraries.
     pip install -e ".[test]"
@@ -126,13 +147,13 @@ commands =
 [testenv:check_codestyle]
 extras = lint
 commands =
-    python -m black --check --diff .
-    /bin/sh -c "flake8 synapse tests scripts scripts-dev contrib synctl {env:PEP8SUFFIX:}"
+    python -m black --check --diff {[base]lint_targets}
+    flake8 {[base]lint_targets} {env:PEP8SUFFIX:}
     {toxinidir}/scripts-dev/config-lint.sh
 
 [testenv:check_isort]
 extras = lint
-commands = /bin/sh -c "isort -c --df --sp setup.cfg synapse tests scripts-dev scripts"
+commands = isort -c --df --sp setup.cfg {[base]lint_targets}
 
 [testenv:check-newsfragment]
 skip_install = True