diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 35cddb26..acace3e5 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -7,31 +7,37 @@ on:
     tags: 'v[0-9]+.*' # only trigger on 'release' tags for PyPi
   # Note that people who fork it need to go to "Actions" tab on their fork and click "I understand my workflows, go ahead and enable them".
   pull_request: # needed to trigger on others' PRs
+  # Note that people who fork it need to go to "Actions" tab on their fork and click "I understand my workflows, go ahead and enable them".
   workflow_dispatch: # needed to trigger workflows manually
   # todo cron?
 
-env:
-  # useful for scripts & sometimes tests to know
-  CI: true
 
 jobs:
   build:
     strategy:
       matrix:
-        platform: [ubuntu-latest, macos-latest] # TODO windows-latest??
-        python-version: [3.7, 3.8, 3.9]
+        platform: [ubuntu-latest, macos-latest,  windows-latest]
+        python-version: ['3.7', '3.8', '3.9']
+        exclude: [
+            # windows runners are pretty scarce, so let's only run one of them..
+            {platform: windows-latest, python-version: '3.7'},
+            {platform: windows-latest, python-version: '3.9'},
+        ]
 
     runs-on: ${{ matrix.platform }}
 
+    # TODO let's at least start running windows for now, will fix later
+    continue-on-error: ${{ matrix.platform == 'windows-latest' }}
+
     steps:
     # ugh https://github.com/actions/toolkit/blob/main/docs/commands.md#path-manipulation
     - run: echo "$HOME/.local/bin" >> $GITHUB_PATH
 
-    - uses: actions/setup-python@v2
+    - uses: actions/setup-python@v3
       with:
         python-version: ${{ matrix.python-version }}
 
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v3
       with:
         submodules: recursive
         fetch-depth: 0  # nicer to have all git history when debugging/for tests
@@ -39,13 +45,16 @@ jobs:
     # uncomment for SSH debugging
     # - uses: mxschmitt/action-tmate@v3
 
-    - run: scripts/ci/run
+    # explicit bash command is necessary for Windows CI runner, otherwise it thinks it's cmd...
+    - run: bash scripts/ci/run
 
-    - uses: actions/upload-artifact@v2
+    - if: matrix.platform == 'ubuntu-latest'  # no need to compute coverage for other platforms
+      uses: actions/upload-artifact@v2
       with:
         name: .coverage.mypy-misc_${{ matrix.platform }}_${{ matrix.python-version }}
         path: .coverage.mypy-misc/
-    - uses: actions/upload-artifact@v2
+    - if: matrix.platform == 'ubuntu-latest'  # no need to compute coverage for other platforms
+      uses: actions/upload-artifact@v2
       with:
         name: .coverage.mypy-core_${{ matrix.platform }}_${{ matrix.python-version }}
         path: .coverage.mypy-core/
@@ -58,11 +67,11 @@ jobs:
     # ugh https://github.com/actions/toolkit/blob/main/docs/commands.md#path-manipulation
     - run: echo "$HOME/.local/bin" >> $GITHUB_PATH
 
-    - uses: actions/setup-python@v2
+    - uses: actions/setup-python@v3
       with:
-        python-version: '3.7'
+        python-version: '3.8'
 
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v3
       with:
         submodules: recursive
 
diff --git a/pytest.ini b/pytest.ini
index b6406e2b..aaa3df2a 100644
--- a/pytest.ini
+++ b/pytest.ini
@@ -9,3 +9,5 @@ addopts =
   # otherwise it won't discover doctests
   # eh? importing too much
   # --doctest-modules
+  # show all test durations (unless they are too short)
+  --durations=0
diff --git a/scripts/ci/run b/scripts/ci/run
index a7ea3bab..47014ece 100755
--- a/scripts/ci/run
+++ b/scripts/ci/run
@@ -1,7 +1,8 @@
-#!/bin/bash -eu
+#!/bin/bash
+set -eu
 
 cd "$(dirname "$0")"
-cd ../..
+cd .. # git root
 
 if ! command -v sudo; then
     # CI or Docker sometimes doesn't have it, so useful to have a dummy
@@ -10,16 +11,31 @@ if ! command -v sudo; then
     }
 fi
 
-if ! [ -z "$CI" ]; then
+if [ -n "${CI-}" ]; then
     # install OS specific stuff here
-    if [[ "$OSTYPE" == "darwin"* ]]; then
+    case "$OSTYPE" in
+    darwin*)
         # macos
         brew install fd
-    else
+        ;;
+    cygwin* | msys* | win*)
+        # windows
+        :
+        ;;
+    *)
+        # must be linux?
         sudo apt update
         sudo apt install fd-find
-    fi
+        ;;
+    esac
 fi
 
-pip3 install --user tox
-tox
+
+PY_BIN="python3"
+# some systems might have python pointing to python3
+if ! command -v python3 &> /dev/null; then
+    PY_BIN="python"
+fi
+
+"$PY_BIN" -m pip install --user tox
+"$PY_BIN" -m tox
diff --git a/setup.py b/setup.py
index 1163008e..31fc3931 100644
--- a/setup.py
+++ b/setup.py
@@ -12,7 +12,7 @@
 ]
 
 
-def main():
+def main() -> None:
     pkg = 'my'
     subpackages = find_namespace_packages('.', include=('my.*',))
     setup(
diff --git a/tox.ini b/tox.ini
index 52bfdfb6..8c22eb38 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,8 @@
 [tox]
 minversion = 3.5
+# https://github.com/tox-dev/tox/issues/20#issuecomment-247788333
+# hack to prevent .tox from crapping to the project directory
+toxworkdir={env:TOXWORKDIR_BASE:}{toxinidir}/.tox
 
 [testenv]
 passenv = CI CI_*