diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index a7b3ac3..1bae00c 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -11,10 +11,18 @@ on:
 jobs:
   build:
 
-    runs-on: ubuntu-latest
+    runs-on: ${{ matrix.os }}
     strategy:
       matrix:
+        os: [ubuntu-latest]
         python-version: [3.6, 3.7, 3.8]
+        include:
+        - python-version: 3.8
+          push-package: true
+        - os: windows-latest
+          python-version: 3.8
+        - os: macos-latest
+          python-version: 3.8
 
     steps:
       - uses: actions/checkout@v2
@@ -24,7 +32,7 @@ jobs:
           python-version: ${{ matrix.python-version }}
       - name: Install dependencies
         run: |
-          make dev-venv
+          make dev-venv SYSTEM_PYTHON=python
       - name: Lint
         run: |
           make dev-lint
@@ -32,17 +40,17 @@ jobs:
         run: |
           make dev-pytest
       - name: Build dist
-        if: matrix.python-version == '3.8'
+        if: matrix.push-package == true
         run: |
           make dev-remove-dist dev-build-dist dev-list-dist-contents dev-test-install-dist
       - name: Publish distribution to Test PyPI
-        if: matrix.python-version == '3.8'
+        if: matrix.push-package == true
         uses: pypa/gh-action-pypi-publish@master
         with:
           password: ${{ secrets.test_pypi_password }}
           repository_url: https://test.pypi.org/legacy/
       - name: Publish distribution to PyPI
-        if: matrix.python-version == '3.8' && startsWith(github.ref, 'refs/tags')
+        if: matrix.push-package == true && startsWith(github.ref, 'refs/tags')
         uses: pypa/gh-action-pypi-publish@master
         with:
           password: ${{ secrets.pypi_password }}
diff --git a/Makefile b/Makefile
index e34745a..1ef7559 100644
--- a/Makefile
+++ b/Makefile
@@ -1,6 +1,15 @@
 VENV = venv
-PIP = $(VENV)/bin/pip
-PYTHON = $(VENV)/bin/python
+
+ifeq ($(OS),Windows_NT)
+	VENV_BIN = $(VENV)/Scripts
+else
+	VENV_BIN = $(VENV)/bin
+endif
+
+PYTHON = $(VENV_BIN)/python
+PIP = $(VENV_BIN)/python -m pip
+
+SYSTEM_PYTHON = python3
 
 VENV_TEMP = venv_temp
 
@@ -30,7 +39,7 @@ venv-clean:
 
 
 venv-create:
-	python3 -m venv $(VENV)
+	$(SYSTEM_PYTHON) -m venv $(VENV)
 
 
 dev-install:
diff --git a/tests/cli_test.py b/tests/cli_test.py
index c5c8971..a02937b 100644
--- a/tests/cli_test.py
+++ b/tests/cli_test.py
@@ -1,8 +1,13 @@
+import logging
 from pathlib import Path
 
+from tf_bodypix.download import BodyPixModelPaths
 from tf_bodypix.cli import main
 
 
+LOGGER = logging.getLogger(__name__)
+
+
 EXAMPLE_IMAGE_URL = (
     r'https://upload.wikimedia.org/wikipedia/commons/thumb/5/5e/'
     r'Person_Of_Interest_-_Panel_%289353656298%29.jpg/'
@@ -69,3 +74,16 @@ def test_should_not_fail_to_replace_background(self, temp_dir: Path):
             '--background=%s' % EXAMPLE_IMAGE_URL,
             '--output=%s' % output_image_path
         ])
+
+    def test_should_list_all_default_model_urls(self, capsys):
+        expected_urls = [
+            value
+            for key, value in BodyPixModelPaths.__dict__.items()
+            if not key.startswith('_')
+        ]
+        main(['list-models'])
+        captured = capsys.readouterr()
+        output_urls = captured.out.splitlines()
+        LOGGER.debug('output_urls: %s', output_urls)
+        missing_urls = set(expected_urls) - set(output_urls)
+        assert not missing_urls
diff --git a/tf_bodypix/cli.py b/tf_bodypix/cli.py
index 0c31142..c6f4c91 100644
--- a/tf_bodypix/cli.py
+++ b/tf_bodypix/cli.py
@@ -253,7 +253,7 @@ def add_arguments(self, parser: argparse.ArgumentParser):
         add_common_arguments(parser)
         parser.add_argument(
             "--storage-url",
-            default="https://storage.googleapis.com/tfjs-models/",
+            default="https://storage.googleapis.com/tfjs-models",
             help="The base URL for the storage containing the models"
         )
 
diff --git a/tf_bodypix/download.py b/tf_bodypix/download.py
index 23c89cb..3c6c8cf 100644
--- a/tf_bodypix/download.py
+++ b/tf_bodypix/download.py
@@ -78,7 +78,7 @@ def download_model(model_path: str) -> str:
     for weights_manifest_path in weights_manifest_paths:
         local_model_json_path = tf.keras.utils.get_file(
             os.path.basename(weights_manifest_path),
-            os.path.join(model_base_path, weights_manifest_path),
+            model_base_path + '/' + weights_manifest_path,
             cache_subdir=cache_subdir,
         )
     return local_model_path
diff --git a/tf_bodypix/utils/s3.py b/tf_bodypix/utils/s3.py
index 867e9ed..6fab53a 100644
--- a/tf_bodypix/utils/s3.py
+++ b/tf_bodypix/utils/s3.py
@@ -1,6 +1,5 @@
 import logging
 
-import os
 import urllib.request
 from xml.etree import ElementTree
 from typing import Iterable
@@ -17,6 +16,8 @@
 
 
 def iter_s3_file_urls(base_url: str) -> Iterable[str]:
+    if not base_url.endswith('/'):
+        base_url += '/'
     marker = None
     while True:
         current_url = base_url
@@ -29,7 +30,7 @@ def iter_s3_file_urls(base_url: str) -> Iterable[str]:
         for item in root.findall(S3_CONTENTS):
             key = item.findtext(S3_KEY)
             LOGGER.debug('key: %s', key)
-            yield os.path.join(base_url, key)
+            yield base_url + key
         next_marker = root.findtext(S3_NEXT_MARKER)
         if not next_marker or next_marker == marker:
             break