diff --git a/.circleci/config.yml b/.circleci/config.yml
index 135a2d05..0dfa7a6d 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -1,44 +1,85 @@
-version: 2
+version: 2.1
+orbs:
+  docker: circleci/docker@2.7.0
+  codecov: codecov/codecov@4.1.0
+  python: circleci/python@2.1.1
+
 jobs:
-  tests:
-    docker:
-      - image: cimg/python:3.11
-        auth:
-          username: $DOCKER_USER
-          password: $DOCKER_PAT
-    working_directory: /tmp/tests
-    environment:
-      - OSF_MIRROR_PATH: /tmp/data/templateflow
-    steps:
-      - checkout:
-          path: /tmp/src/templateflow
+  build:
+    executor:
+      name: python/default
+      tag: '3.12'
+
+    # docker:
+    #   - auth:
+    #       username: $DOCKER_USERNAME
+    #       password: $DOCKER_PASSWORD
 
+    steps:
+      - checkout
       - run:
-          name: Generate requirements.txt
           command: |
-            python /tmp/src/templateflow/.maint/update_requirements.py
-
-      - restore_cache:
-          keys:
-            - deps-v11-{{ checksum "/tmp/src/templateflow/dev-requirements.txt"}}-{{ epoch }}
-            - deps-v11-{{ checksum "/tmp/src/templateflow/dev-requirements.txt"}}-
-            - deps-v11-
+            echo 'build' > requirements.txt
+            echo 'wheel' >> requirements.txt
+            echo 'twine' >> requirements.txt
+      - python/install-packages:
+          pkg-manager: pip
+          cache-version: build-v1
       - run:
-          name: Prepare environment
           command: |
-            python -m venv /tmp/venv
-            source /tmp/venv/bin/activate
-            python -m pip install -U pip
-            python -m pip install -r /tmp/src/templateflow/dev-requirements.txt
-            python -m pip install -U "datalad ~= 0.19.0"
-            python -m pip install -U build hatch twine pkginfo codecov
+            python -m build
+            python -m twine check dist/*
+          name: Test packaging
+      - persist_to_workspace:
+          root: ~/project
+          paths:
+            - .
+
+  deploy_pypi:
+    executor:
+      name: python/default
+      tag: '3.12'
+
+    # docker:
+    #   - auth:
+    #       username: $DOCKER_USERNAME
+    #       password: $DOCKER_PASSWORD
+
+    steps:
+      - attach_workspace:
+          at: ~/project
+
+      - python/install-packages:
+          args: twine
+          pkg-manager: pip
 
+      - run:
+          command: python -m twine upload dist/*
+          name: Upload to Pypi
+
+  tests:
+    executor:
+      name: python/default
+      tag: '3.12'
+
+    # docker:
+    #   - auth:
+    #       username: $DOCKER_USERNAME
+    #       password: $DOCKER_PASSWORD
+
+    environment:
+      - OSF_MIRROR_PATH: /tmp/data/templateflow
+    steps:
+      - restore_cache:
+          keys:
+            - annex-v1-{{ epoch }}
+            - annex-v1-
       - run:
           name: Install git and git-annex
           command: |
             if [[ ! -e "/tmp/cache/git-annex-standalone.tar.gz" ]]; then
               wget -O- http://neuro.debian.net/lists/focal.us-ca.full | sudo tee /etc/apt/sources.list.d/neurodebian.sources.list
-              sudo apt-key add /tmp/src/templateflow/.neurodebian/neurodebian.gpg
+              sudo apt-key add .neurodebian/neurodebian.gpg
               sudo apt-key adv --recv-keys --keyserver hkps://keys.openpgp.org 0xA5D32F012649A5A9 || true
               sudo apt update && sudo apt-get install -y --no-install-recommends git-annex-standalone
               mkdir -p /tmp/cache
@@ -50,83 +91,80 @@ jobs:
             git config --global user.email "email@domain.com"
 
       - save_cache:
-          key: deps-v11-{{ checksum "/tmp/src/templateflow/dev-requirements.txt"}}-{{ epoch }}
+          key: annex-v1-{{ epoch }}
           paths:
             - "/tmp/cache"
-            - "/tmp/venv"
+
+      - attach_workspace:
+          at: ~/project
 
       - run:
-          name: Test packaging
           command: |
-            source /tmp/venv/bin/activate
-            cd /tmp/src/templateflow
-            python -m build
-            python -m twine check dist/*
+            python .maint/update_requirements.py
+          name: Generate requirements.txt
+
+      - python/install-packages:
+          pip-dependency-file: dev-requirements.txt
+          pkg-manager: pip
+          cache-version: v1
 
       - run:
-          name: Run tests (w/ DataLad)
+          name: Run tests (config and others)
           command: |
-            source /tmp/venv/bin/activate
-            export TEMPLATEFLOW_USE_DATALAD=on
-            pytest --junit-xml=/tmp/tests/datalad.xml --cov templateflow --cov-report xml:/tmp/cov_api_dl.xml \
-                   --doctest-modules /tmp/src/templateflow/templateflow
+            python -m pytest \
+                   --junit-xml=~/tests/conftests.xml --cov templateflow --cov-report xml:~/coverage/cov_config.xml \
+                   templateflow/tests/
+
+      - codecov/upload:
+          file: ~/coverage/cov_config.xml
+          flags: config
+          upload_name: General
 
       - run:
-          name: Submit api test coverage
+          name: Run tests (w/ DataLad)
           command: |
-            source /tmp/venv/bin/activate
-            codecov --file /tmp/cov_api_dl.xml --root /tmp/src/templateflow \
-                --flags api,datalad -e CIRCLE_JOB
+            mkdir -p ~/tests/ ~/coverage/
+            export TEMPLATEFLOW_USE_DATALAD=on
+            python -m pytest \
+                   --junit-xml=~/tests/datalad.xml --cov templateflow --cov-report xml:~/coverage/cov_api_dl.xml \
+                   --doctest-modules templateflow/api.py
+
+      - codecov/upload:
+          file: ~/coverage/cov_api_dl.xml
+          flags: api,datalad
+          upload_name: Datalad tests
 
       - run:
           name: Run tests (pulling from S3)
           command: |
-            source /tmp/venv/bin/activate
             export TEMPLATEFLOW_USE_DATALAD=off
             export TEMPLATEFLOW_HOME=$HOME/templateflow-s3
-            pytest --junit-xml=/tmp/tests/s3.xml --cov templateflow --cov-report xml:/tmp/cov_api_s3.xml \
-                   --doctest-modules /tmp/src/templateflow/templateflow/api.py
+            python -m pytest \
+                   --junit-xml=~/tests/s3.xml --cov templateflow --cov-report xml:~/coverage/cov_api_s3.xml \
+                   --doctest-modules templateflow/api.py
 
-      - run:
-          name: Submit api test coverage
-          command: |
-            source /tmp/venv/bin/activate
-            codecov --file /tmp/cov_api_s3.xml --root /tmp/src/templateflow \
-                --flags api,s3 -e CIRCLE_JOB
+      - codecov/upload:
+          file: ~/coverage/cov_api_s3.xml
+          flags: api,s3
+          upload_name: S3 tests
 
       - run:
           name: Run tests (w/ DataLad, bypassed via S3)
           command: |
-            source /tmp/venv/bin/activate
             export TEMPLATEFLOW_USE_DATALAD=off
             export TEMPLATEFLOW_HOME=$HOME/templateflow-clean
             datalad install -r -s https://github.com/templateflow/templateflow $TEMPLATEFLOW_HOME
-            pytest --junit-xml=/tmp/tests/dl+s3.xml --cov templateflow --cov-report xml:/tmp/cov_api_dl_s3.xml \
-                   --doctest-modules /tmp/src/templateflow/templateflow/api.py
+            python -m pytest \
+                   --junit-xml=~/tests/dl+s3.xml --cov templateflow --cov-report xml:~/coverage/cov_api_dl_s3.xml \
+                   --doctest-modules templateflow/api.py
 
-      - run:
-          name: Submit api test coverage
-          command: |
-            source /tmp/venv/bin/activate
-            codecov --file /tmp/cov_api_dl_s3.xml --root /tmp/src/templateflow \
-                --flags api,dls3 -e CIRCLE_JOB
-
-      - run:
-          name: Run tests (config, parameterized TEMPLATEFLOW_USE_DATALAD)
-          command: |
-            source /tmp/venv/bin/activate
-            pytest --junit-xml=/tmp/tests/conftests.xml --cov templateflow --cov-report xml:/tmp/cov_config.xml \
-                   /tmp/src/templateflow/templateflow/conf/tests/test_conf.py
-
-      - run:
-          name: Submit config test coverage
-          command: |
-            source /tmp/venv/bin/activate
-            codecov --file /tmp/cov_config.xml --root /tmp/src/templateflow \
-                --flags config -e CIRCLE_JOB
+      - codecov/upload:
+          file: ~/coverage/cov_api_dl_s3.xml
+          flags: api,dls3
+          upload_name: Datalad-S3-bypass
 
       - store_test_results:
-          path: /tmp/tests
+          path: ~/tests
 
   build_docs:
     machine:
@@ -179,54 +217,38 @@ jobs:
       - store_artifacts:
           path: ~/html
 
-  deploy_pypi:
-    docker:
-      - image: cimg/python:3.9
-    working_directory: /tmp/src/templateflow
-    steps:
-      - attach_workspace:
-          at: /tmp
-
-      - checkout:
-          path: /tmp/src/templateflow
-
-      - run:
-          name: Generate requirements.txt
-          command: |
-            python /tmp/src/templateflow/.maint/update_requirements.py
-
-      - restore_cache:
-          keys:
-            - deps-v11-{{ checksum "/tmp/src/templateflow/dev-requirements.txt"}}-{{ epoch }}
-            - deps-v11-{{ checksum "/tmp/src/templateflow/dev-requirements.txt"}}-
-            - deps-v11-
-
-      - run:
-          name: Deploy to PyPi
-          command: |
-            source /tmp/venv/bin/activate
-            python -m pip install build -U twine pkginfo
-            python -m build
-            python -m twine check dist/*
-            python -m twine upload dist/*
-
 workflows:
   version: 2
   build_test_deploy:
     jobs:
+      - build:
+          context:
+            - nipreps-common
+          filters:
+            branches:
+              ignore:
+                - /docs?\/.*/
+            tags:
+              only: /.*/
+
       - tests:
           context:
             - nipreps-common
+          requires:
+            - build
           filters:
             branches:
               ignore:
                 - /docs?\/.*/
             tags:
               only: /.*/
+
       - deploy_pypi:
           context:
             - nipreps-common
           requires:
+            - build
+            - tests
             - build_docs
           filters:
             branches:
diff --git a/.maint/update_requirements.py b/.maint/update_requirements.py
index bbce29a9..f3d2e110 100755
--- a/.maint/update_requirements.py
+++ b/.maint/update_requirements.py
@@ -16,13 +16,13 @@
 reqs_dev = repo_root / 'dev-requirements.txt'
 
 requirements = [
-    Requirement(req)
-    for req in loads(pyproject.read_text())['project']['dependencies']
+    Requirement(req) for req in loads(pyproject.read_text())['project']['dependencies']
 ]
 
 requirements_dev = [
     Requirement(req)
-    for req in loads(pyproject.read_text())['project']['optional-dependencies']['test']
+    for group in ('test', 'datalad')
+    for req in loads(pyproject.read_text())['project']['optional-dependencies'][group]
 ]
 
 script_name = Path(__file__).relative_to(repo_root)
diff --git a/pyproject.toml b/pyproject.toml
index 507d5146..51e999f9 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -37,13 +37,15 @@ Documentation = "https://www.templateflow.org/python-client/"
 
 [project.optional-dependencies]
 test = [
+    "coverage ~= 5.0.0",
     "pytest",
+    "pytest-cov",
+    "pytest-env",
     "pytest-xdist",
-    "pytest-cov == 2.5.1",
-    "coverage",
+    "toml",
 ]
 datalad = [
-    "datalad ~= 0.19.0"
+    "datalad ~= 1.0.0"
 ]
 doc = [
     "nbsphinx",
@@ -113,7 +115,7 @@ per-file-ignores = [
 
 [tool.pytest.ini_options]
 norecursedirs = [".git"]
-addopts = "-svx --doctest-modules"
+addopts = "-svx"
 doctest_optionflags = "ALLOW_UNICODE NORMALIZE_WHITESPACE ELLIPSIS"
 env = "PYTHONHASHSEED=0"
 filterwarnings = ["ignore::DeprecationWarning"]
@@ -121,7 +123,7 @@ junit_family = "xunit2"
 
 [tool.coverage.run]
 branch = true
-concurrency = 'multiprocessing'
+concurrency = ['multiprocessing']
 omit = [
     '*/tests/*',
     '*/conftest.py',
diff --git a/templateflow/__init__.py b/templateflow/__init__.py
index 2d2a5ce5..ee150506 100644
--- a/templateflow/__init__.py
+++ b/templateflow/__init__.py
@@ -21,6 +21,7 @@
 #     https://www.nipreps.org/community/licensing/
 #
 """TemplateFlow is the Zone of Templates."""
+
 from datetime import datetime as _dt
 from datetime import timezone as _tz
 
@@ -30,6 +31,7 @@
     from ._version import __version__
 except ModuleNotFoundError:
     from importlib.metadata import PackageNotFoundError, version
+
     try:
         __version__ = version(__packagename__)
     except PackageNotFoundError:
diff --git a/templateflow/_loader.py b/templateflow/_loader.py
index 123a17cd..37d33f9e 100644
--- a/templateflow/_loader.py
+++ b/templateflow/_loader.py
@@ -24,6 +24,7 @@
 
 .. autoclass:: Loader
 """
+
 from __future__ import annotations
 
 import atexit
diff --git a/templateflow/api.py b/templateflow/api.py
index 19f42441..6d1d51f0 100644
--- a/templateflow/api.py
+++ b/templateflow/api.py
@@ -21,6 +21,7 @@
 #     https://www.nipreps.org/community/licensing/
 #
 """TemplateFlow's Python Client."""
+
 import sys
 from json import loads
 from pathlib import Path
@@ -35,9 +36,7 @@
     requires_layout,
 )
 
-_layout_dir = tuple(
-    item for item in dir(TF_LAYOUT) if item.startswith('get_')
-)
+_layout_dir = tuple(item for item in dir(TF_LAYOUT) if item.startswith('get_'))
 
 
 @requires_layout
@@ -92,10 +91,9 @@ def ls(template, **kwargs):
         kwargs['extension'] = _normalize_ext(kwargs['extension'])
 
     return [
-        Path(p) for p in TF_LAYOUT.get(
-            template=Query.ANY if template is None else template,
-            return_type='file',
-            **kwargs
+        Path(p)
+        for p in TF_LAYOUT.get(
+            template=Query.ANY if template is None else template, return_type='file', **kwargs
         )
     ]
 
@@ -176,25 +174,23 @@ def get(template, raise_empty=False, **kwargs):
     not_fetched = [str(p) for p in out_file if not p.is_file() or p.stat().st_size == 0]
 
     if not_fetched:
-        msg = 'Could not fetch template files: %s.' % ', '.join(not_fetched)
+        msg = 'Could not fetch template files: {}.'.format(', '.join(not_fetched))
         if dl_missing and not TF_USE_DATALAD:
             msg += (
-                """\
-The $TEMPLATEFLOW_HOME folder %s seems to contain an initiated DataLad \
+                f"""\
+The $TEMPLATEFLOW_HOME folder {TF_LAYOUT.root} seems to contain an initiated DataLad \
 dataset, but the environment variable $TEMPLATEFLOW_USE_DATALAD is not \
 set or set to one of (false, off, 0). Please set $TEMPLATEFLOW_USE_DATALAD \
 on (possible values: true, on, 1)."""
-                % TF_LAYOUT.root
             )
 
         if s3_missing and TF_USE_DATALAD:
             msg += (
-                """\
-The $TEMPLATEFLOW_HOME folder %s seems to contain an plain \
+                f"""\
+The $TEMPLATEFLOW_HOME folder {TF_LAYOUT.root} seems to contain an plain \
 dataset, but the environment variable $TEMPLATEFLOW_USE_DATALAD is \
 set to one of (true, on, 1). Please set $TEMPLATEFLOW_USE_DATALAD \
 off (possible values: false, off, 0)."""
-                % TF_LAYOUT.root
             )
 
         raise RuntimeError(msg)
@@ -251,7 +247,7 @@ def get_metadata(template):
 
     """
     tf_home = Path(TF_LAYOUT.root)
-    filepath = tf_home / ('tpl-%s' % template) / 'template_description.json'
+    filepath = tf_home / (f'tpl-{template}') / 'template_description.json'
 
     # Ensure that template is installed and file is available
     if not filepath.is_file():
@@ -324,7 +320,7 @@ def _s3_get(filepath):
     path = filepath.relative_to(TF_LAYOUT.root).as_posix()
     url = f'{TF_S3_ROOT}/{path}'
 
-    print('Downloading %s' % url, file=stderr)
+    print(f'Downloading {url}', file=stderr)
     # Streaming, so we can iterate over the response.
     r = requests.get(url, stream=True, timeout=TF_GET_TIMEOUT)
 
diff --git a/templateflow/cli.py b/templateflow/cli.py
index 22b06f14..f536eed1 100644
--- a/templateflow/cli.py
+++ b/templateflow/cli.py
@@ -21,6 +21,7 @@
 #     https://www.nipreps.org/community/licensing/
 #
 """The TemplateFlow Python Client command-line interface (CLI)."""
+
 from __future__ import annotations
 
 import json
@@ -31,20 +32,20 @@
 
 from templateflow import __package__, api
 from templateflow._loader import Loader as _Loader
-from templateflow.conf import TF_HOME, TF_USE_DATALAD, TF_AUTOUPDATE
+from templateflow.conf import TF_AUTOUPDATE, TF_HOME, TF_USE_DATALAD
 
 load_data = _Loader(__package__)
 
 ENTITY_SHORTHANDS = {
     # 'template': ('--tpl', '-t'),
-    'resolution': ('--res', ),
-    'density': ('--den', ),
-    'atlas': ('-a', ),
-    'suffix': ('-s', ),
+    'resolution': ('--res',),
+    'density': ('--den',),
+    'atlas': ('-a',),
+    'suffix': ('-s',),
     'desc': ('-d', '--description'),
     'extension': ('--ext', '-x'),
-    'label': ('-l', ),
-    'segmentation': ('--seg', ),
+    'label': ('-l',),
+    'segmentation': ('--seg',),
 }
 ENTITY_EXCLUDE = {'template', 'description'}
 TEMPLATE_LIST = api.get_templates()
@@ -57,16 +58,12 @@ def _nulls(s):
 def entity_opts():
     """Attaches all entities as options to the command."""
 
-    entities = json.loads(
-        Path(load_data('conf/config.json')).read_text()
-    )['entities']
+    entities = json.loads(Path(load_data('conf/config.json')).read_text())['entities']
 
     args = [
-        (
-            f"--{e['name']}",
-            *ENTITY_SHORTHANDS.get(e['name'], ())
-        )
-        for e in entities if e['name'] not in ENTITY_EXCLUDE
+        (f"--{e['name']}", *ENTITY_SHORTHANDS.get(e['name'], ()))
+        for e in entities
+        if e['name'] not in ENTITY_EXCLUDE
     ]
 
     def decorator(f: FC) -> FC:
@@ -135,9 +132,7 @@ def update(local, overwrite):
 def ls(template, **kwargs):
     """List the assets corresponding to template and optional filters."""
     entities = {k: _nulls(v) for k, v in kwargs.items() if v != ''}
-    click.echo(
-        '\n'.join(f'{match}' for match in api.ls(template, **entities))
-    )
+    click.echo('\n'.join(f'{match}' for match in api.ls(template, **entities)))
 
 
 @main.command()
@@ -146,9 +141,7 @@ def ls(template, **kwargs):
 def get(template, **kwargs):
     """Fetch the assets corresponding to template and optional filters."""
     entities = {k: _nulls(v) for k, v in kwargs.items() if v != ''}
-    click.echo(
-        '\n'.join(f'{match}' for match in api.get(template, **entities))
-    )
+    click.echo('\n'.join(f'{match}' for match in api.get(template, **entities)))
 
 
 if __name__ == '__main__':
diff --git a/templateflow/conf/__init__.py b/templateflow/conf/__init__.py
index a75bfd85..85940474 100644
--- a/templateflow/conf/__init__.py
+++ b/templateflow/conf/__init__.py
@@ -1,4 +1,5 @@
 """Configuration and settings."""
+
 import re
 from contextlib import suppress
 from functools import wraps
@@ -35,7 +36,7 @@ def _env_to_bool(envvar: str, default: bool) -> bool:
 
 
 TF_DEFAULT_HOME = Path.home() / '.cache' / 'templateflow'
-TF_HOME = Path(getenv('TEMPLATEFLOW_HOME', str(TF_DEFAULT_HOME)))
+TF_HOME = Path(getenv('TEMPLATEFLOW_HOME', str(TF_DEFAULT_HOME))).absolute()
 TF_GITHUB_SOURCE = 'https://github.com/templateflow/templateflow.git'
 TF_S3_ROOT = 'https://templateflow.s3.amazonaws.com'
 TF_USE_DATALAD = _env_to_bool('TEMPLATEFLOW_USE_DATALAD', False)
@@ -43,9 +44,19 @@ def _env_to_bool(envvar: str, default: bool) -> bool:
 TF_CACHED = True
 TF_GET_TIMEOUT = 10
 
+if TF_USE_DATALAD:
+    try:
+        from datalad.api import install
+    except ImportError:
+        warn('DataLad is not installed ➔ disabled.', stacklevel=2)
+        TF_USE_DATALAD = False
+
+if not TF_USE_DATALAD:
+    from templateflow.conf._s3 import update as _update_s3
+
 
 def _init_cache():
-    global TF_HOME, TF_CACHED, TF_USE_DATALAD
+    global TF_CACHED
 
     if not TF_HOME.exists() or not list(TF_HOME.iterdir()):
         TF_CACHED = False
@@ -58,17 +69,9 @@ def _init_cache():
             stacklevel=2,
         )
         if TF_USE_DATALAD:
-            try:
-                from datalad.api import install
-            except ImportError:
-                TF_USE_DATALAD = False
-            else:
-                TF_HOME.parent.mkdir(exist_ok=True, parents=True)
-                install(path=str(TF_HOME), source=TF_GITHUB_SOURCE, recursive=True)
-
-        if not TF_USE_DATALAD:
-            from ._s3 import update as _update_s3
-
+            TF_HOME.parent.mkdir(exist_ok=True, parents=True)
+            install(path=str(TF_HOME), source=TF_GITHUB_SOURCE, recursive=True)
+        else:
             _update_s3(TF_HOME, local=True, overwrite=TF_AUTOUPDATE, silent=True)
 
 
@@ -85,9 +88,7 @@ def wrapper(*args, **kwargs):
         if TF_LAYOUT is None:
             from bids import __version__
 
-            raise RuntimeError(
-                f'A layout with PyBIDS <{__version__}> could not be initiated'
-            )
+            raise RuntimeError(f'A layout with PyBIDS <{__version__}> could not be initiated')
         return func(*args, **kwargs)
 
     return wrapper
@@ -95,8 +96,8 @@ def wrapper(*args, **kwargs):
 
 def update(local=False, overwrite=True, silent=False):
     """Update an existing DataLad or S3 home."""
-    if TF_USE_DATALAD and _update_datalad():
-        success = True
+    if TF_USE_DATALAD:
+        success = _update_datalad()
     else:
         from ._s3 import update as _update_s3
 
@@ -116,7 +117,6 @@ def update(local=False, overwrite=True, silent=False):
 
 def wipe():
     """Clear the cache if functioning in S3 mode."""
-    global TF_USE_DATALAD, TF_HOME
 
     if TF_USE_DATALAD:
         print('TemplateFlow is configured in DataLad mode, wipe() has no effect')
@@ -131,9 +131,7 @@ def _onerror(func, path, excinfo):
         from pathlib import Path
 
         if Path(path).exists():
-            print(
-                f'Warning: could not delete <{path}>, please clear the cache manually.'
-            )
+            print(f'Warning: could not delete <{path}>, please clear the cache manually.')
 
     rmtree(TF_HOME, onerror=_onerror)
     _init_cache()
diff --git a/templateflow/conf/_s3.py b/templateflow/conf/_s3.py
index d70c3cb3..eda04909 100644
--- a/templateflow/conf/_s3.py
+++ b/templateflow/conf/_s3.py
@@ -21,6 +21,7 @@
 #     https://www.nipreps.org/community/licensing/
 #
 """Tooling to handle S3 downloads."""
+
 from pathlib import Path
 from tempfile import mkstemp
 
@@ -86,18 +87,18 @@ def _update_skeleton(skel_file, dest, overwrite=True, silent=False):
             newfiles = allfiles
         else:
             current_files = [s.relative_to(dest) for s in dest.glob('**/*')]
-            existing = sorted({'%s/' % s.parent for s in current_files}) + [
+            existing = sorted({f'{s.parent}/' for s in current_files}) + [
                 str(s) for s in current_files
             ]
             newfiles = sorted(set(allfiles) - set(existing))
 
         if newfiles:
             if not silent:
-                print(
-                    'Updating TEMPLATEFLOW_HOME using S3. Adding:\n%s'
-                    % '\n'.join(newfiles)
-                )
+                print('Updating TEMPLATEFLOW_HOME using S3. Adding:')
+
             for fl in newfiles:
+                if not silent:
+                    print(fl)
                 localpath = dest / fl
                 if localpath.exists():
                     continue
diff --git a/templateflow/conf/bids.py b/templateflow/conf/bids.py
index 3430e711..a143e4de 100644
--- a/templateflow/conf/bids.py
+++ b/templateflow/conf/bids.py
@@ -21,6 +21,7 @@
 #     https://www.nipreps.org/community/licensing/
 #
 """Extending pyBIDS for querying TemplateFlow."""
+
 from bids.layout import BIDSLayout, add_config_paths
 
 from templateflow.conf import load_data
@@ -34,7 +35,5 @@ def __repr__(self):
         s = """\
 TemplateFlow Layout
  - Home: {}
- - Templates: {}.""".format(
-            self.root, ', '.join(sorted(self.get_templates()))
-        )
+ - Templates: {}.""".format(self.root, ', '.join(sorted(self.get_templates())))
         return s
diff --git a/templateflow/conf/tests/__init__.py b/templateflow/conf/tests/__init__.py
deleted file mode 100644
index e69de29b..00000000
diff --git a/templateflow/conf/tests/test_conf.py b/templateflow/conf/tests/test_conf.py
deleted file mode 100644
index 355bbd12..00000000
--- a/templateflow/conf/tests/test_conf.py
+++ /dev/null
@@ -1,151 +0,0 @@
-# emacs: -*- mode: python; py-indent-offset: 4; indent-tabs-mode: nil -*-
-# vi: set ft=python sts=4 ts=4 sw=4 et:
-#
-# Copyright 2024 The NiPreps Developers <nipreps@gmail.com>
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#     http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-#
-# We support and encourage derived works from this project, please read
-# about our expectations at
-#
-#     https://www.nipreps.org/community/licensing/
-#
-from importlib import reload
-from shutil import rmtree
-
-import pytest
-
-from templateflow import conf as tfc
-
-
-def _find_message(lines, msg, reverse=True):
-    if isinstance(lines, str):
-        lines = lines.splitlines()
-
-    for line in reversed(lines):
-        if line.strip().startswith(msg):
-            return True
-    return False
-
-
-@pytest.mark.parametrize('use_datalad', ['off', 'on'])
-def test_conf_init(monkeypatch, tmp_path, capsys, use_datalad):
-    """Check the correct functioning of config set-up."""
-    home = (tmp_path / '-'.join(('tf', 'dl', use_datalad))).resolve()
-    monkeypatch.setenv('TEMPLATEFLOW_USE_DATALAD', use_datalad)
-    monkeypatch.setenv('TEMPLATEFLOW_HOME', str(home))
-
-    # First execution, the S3 stub is created (or datalad install)
-    reload(tfc)
-    assert tfc.TF_CACHED is False
-    assert str(tfc.TF_HOME) == str(home)
-
-    reload(tfc)
-    assert tfc.TF_CACHED is True
-    assert str(tfc.TF_HOME) == str(home)
-
-
-@pytest.mark.parametrize('use_datalad', ['off', 'on'])
-def test_setup_home(monkeypatch, tmp_path, capsys, use_datalad):
-    """Check the correct functioning of the installation hook."""
-    home = (tmp_path / '-'.join(('tf', 'dl', use_datalad))).resolve()
-    monkeypatch.setenv('TEMPLATEFLOW_USE_DATALAD', use_datalad)
-    monkeypatch.setenv('TEMPLATEFLOW_HOME', str(home))
-
-    reload(tfc)
-    # First execution, the S3 stub is created (or datalad install)
-    assert tfc.TF_CACHED is False
-    assert tfc.setup_home() is False
-
-    out = capsys.readouterr().out
-    assert _find_message(out, 'TemplateFlow was not cached')
-    assert ('TEMPLATEFLOW_HOME=%s' % home) in out
-    assert home.exists()
-    assert len(list(home.iterdir())) > 0
-
-    updated = tfc.setup_home(force=True)  # Templateflow is now cached
-    out = capsys.readouterr()[0]
-    assert _find_message(out, 'TemplateFlow was not cached') is False
-
-    if use_datalad == 'on':
-        assert _find_message(out, 'Updating TEMPLATEFLOW_HOME using DataLad')
-        assert updated is True
-
-    elif use_datalad == 'off':
-        # At this point, S3 should be up-to-date
-        assert updated is False
-        assert _find_message(out, 'TEMPLATEFLOW_HOME directory (S3 type) was up-to-date.')
-
-        # Let's force an update
-        rmtree(str(home / 'tpl-MNI152NLin2009cAsym'))
-        updated = tfc.setup_home(force=True)
-        out = capsys.readouterr()[0]
-        assert updated is True
-        assert _find_message(out, 'Updating TEMPLATEFLOW_HOME using S3.')
-
-    reload(tfc)
-    assert tfc.TF_CACHED is True
-    updated = tfc.setup_home()  # Templateflow is now cached
-    out = capsys.readouterr()[0]
-    assert not _find_message(out, 'TemplateFlow was not cached')
-
-    if use_datalad == 'on':
-        assert _find_message(out, 'Updating TEMPLATEFLOW_HOME using DataLad')
-        assert updated is True
-
-    elif use_datalad == 'off':
-        # At this point, S3 should be up-to-date
-        assert updated is False
-        assert _find_message(out, 'TEMPLATEFLOW_HOME directory (S3 type) was up-to-date.')
-
-        # Let's force an update
-        rmtree(str(home / 'tpl-MNI152NLin2009cAsym'))
-        updated = tfc.setup_home()
-        out = capsys.readouterr()[0]
-        assert updated is True
-        assert _find_message(out, 'Updating TEMPLATEFLOW_HOME using S3.')
-
-
-def test_layout(monkeypatch, tmp_path):
-    monkeypatch.setenv('TEMPLATEFLOW_USE_DATALAD', 'off')
-
-    lines = ('%s' % tfc.TF_LAYOUT).splitlines()
-    assert lines[0] == 'TemplateFlow Layout'
-    assert lines[1] == ' - Home: %s' % tfc.TF_HOME
-    assert lines[2].startswith(' - Templates:')
-
-
-def test_layout_errors(monkeypatch):
-    """Check regression of #71."""
-    import builtins
-    import sys
-    from importlib import __import__ as oldimport
-
-    @tfc.requires_layout
-    def myfunc():
-        return 'okay'
-
-    def mock_import(name, globals=None, locals=None, fromlist=(), level=0):  # noqa: A002
-        if name == 'bids':
-            raise ModuleNotFoundError
-        return oldimport(name, globals=globals, locals=locals, fromlist=fromlist, level=level)
-
-    with monkeypatch.context() as m:
-        m.setattr(tfc, 'TF_LAYOUT', None)
-        with pytest.raises(RuntimeError):
-            myfunc()
-
-        m.delitem(sys.modules, 'bids')
-        m.setattr(builtins, '__import__', mock_import)
-        with pytest.raises(ImportError):
-            myfunc()
diff --git a/templateflow/conf/tests/test_s3.py b/templateflow/conf/tests/test_s3.py
deleted file mode 100644
index 0971f662..00000000
--- a/templateflow/conf/tests/test_s3.py
+++ /dev/null
@@ -1,74 +0,0 @@
-# emacs: -*- mode: python; py-indent-offset: 4; indent-tabs-mode: nil -*-
-# vi: set ft=python sts=4 ts=4 sw=4 et:
-#
-# Copyright 2024 The NiPreps Developers <nipreps@gmail.com>
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#     http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-#
-# We support and encourage derived works from this project, please read
-# about our expectations at
-#
-#     https://www.nipreps.org/community/licensing/
-#
-"""Check S3-type repo tooling."""
-# import pytest
-from pathlib import Path
-
-import requests
-
-from .. import _s3 as s3
-
-
-def test_get_skel_file(monkeypatch):
-    """Exercise the skeleton file generation."""
-    local_md5 = s3.TF_SKEL_MD5
-    monkeypatch.setattr(s3, 'TF_SKEL_MD5', 'invent')
-    new_skel = s3._get_skeleton_file()
-    assert new_skel is not None
-    assert Path(new_skel).exists()
-    assert Path(new_skel).stat().st_size > 0
-
-    latest_md5 = (
-        requests.get(s3.TF_SKEL_URL(release='master', ext='md5', allow_redirects=True), timeout=10)
-        .content.decode()
-        .split()[0]
-    )
-    monkeypatch.setattr(s3, 'TF_SKEL_MD5', latest_md5)
-    assert s3._get_skeleton_file() is None
-
-    monkeypatch.setattr(s3, 'TF_SKEL_MD5', local_md5)
-    monkeypatch.setattr(s3, 'TF_SKEL_URL', 'http://weird/{release}/{ext}'.format)
-    assert s3._get_skeleton_file() is None
-
-    monkeypatch.setattr(
-        s3, 'TF_SKEL_URL', s3.TF_SKEL_URL(release='{release}', ext='{ext}z').format
-    )
-    assert s3._get_skeleton_file() is None
-
-
-def test_update_s3(tmp_path, monkeypatch):
-    """Exercise updating the S3 skeleton."""
-    newhome = tmp_path / 'templateflow'
-    assert s3.update(newhome)
-    assert not s3.update(newhome, overwrite=False)
-    for p in (newhome / 'tpl-MNI152NLin6Sym').glob('*.nii.gz'):
-        p.unlink()
-    assert s3.update(newhome, overwrite=False)
-
-    # This should cover the remote zip file fetching
-    monkeypatch.setattr(s3, 'TF_SKEL_MD5', 'invent')
-    assert s3.update(newhome, local=False)
-    assert not s3.update(newhome, local=False, overwrite=False)
-    for p in (newhome / 'tpl-MNI152NLin6Sym').glob('*.nii.gz'):
-        p.unlink()
-    assert s3.update(newhome, local=False, overwrite=False)
diff --git a/templateflow/tests/test_api.py b/templateflow/tests/test_api.py
index fc773319..fe2aea3b 100644
--- a/templateflow/tests/test_api.py
+++ b/templateflow/tests/test_api.py
@@ -24,7 +24,7 @@
 
 import pytest
 
-from .. import api
+from templateflow import api
 
 
 class Bibtex:
@@ -154,9 +154,7 @@ def assert_same(self, other):
 journal={Cerebral Cortex}
 }"""
 
-fslr_lbib = (
-    'https://github.com/Washington-University/HCPpipelines/tree/master/global/templates'
-)
+fslr_lbib = 'https://github.com/Washington-University/HCPpipelines/tree/master/global/templates'
 
 fsaverage_fbib = """\
 @article{Fischl_1999,
@@ -181,9 +179,7 @@ def assert_same(self, other):
         ('fsLR', fslr_urls, fslr_fbib, fslr_lbib),
         (
             'fsaverage',
-            [
-                'https://doi.org/10.1002/(sici)1097-0193(1999)8:4%3C272::aid-hbm10%3E3.0.co;2-4'
-            ],
+            ['https://doi.org/10.1002/(sici)1097-0193(1999)8:4%3C272::aid-hbm10%3E3.0.co;2-4'],
             fsaverage_fbib,
             None,
         ),
diff --git a/templateflow/tests/test_conf.py b/templateflow/tests/test_conf.py
index 461d5bd2..c30ea877 100644
--- a/templateflow/tests/test_conf.py
+++ b/templateflow/tests/test_conf.py
@@ -21,32 +21,146 @@
 #     https://www.nipreps.org/community/licensing/
 #
 """Tests the config module."""
-from pathlib import Path
+
+from importlib import reload
+from shutil import rmtree
 
 import pytest
 
-from .. import api, conf
-
-
-@pytest.mark.skipif(conf.TF_USE_DATALAD, reason='S3 only')
-def test_update_s3(tmp_path):
-    conf.TF_HOME = tmp_path / 'templateflow'
-    conf.TF_HOME.mkdir(exist_ok=True)
-
-    # replace TF_SKEL_URL with the path of a legacy skeleton
-    _skel_url = conf._s3.TF_SKEL_URL
-    conf._s3.TF_SKEL_URL = (
-        'https://github.com/templateflow/python-client/raw/0.5.0/'
-        'templateflow/conf/templateflow-skel.{ext}'.format
-    )
-    # initialize templateflow home, making sure to pull the legacy skeleton
-    conf.update(local=False)
-    # ensure we can grab a file
-    assert Path(api.get('MNI152NLin2009cAsym', resolution=2, desc='brain', suffix='mask')).exists()
-    # and ensure we can't fetch one that doesn't yet exist
-    assert not api.get('Fischer344', hemi='L', desc='brain', suffix='mask')
-
-    # refresh the skeleton using the most recent skeleton
-    conf._s3.TF_SKEL_URL = _skel_url
-    conf.update(local=True, overwrite=True)
-    assert Path(api.get('Fischer344', hemi='L', desc='brain', suffix='mask')).exists()
+from templateflow import conf as tfc
+
+
+def _find_message(lines, msg, reverse=True):
+    if isinstance(lines, str):
+        lines = lines.splitlines()
+
+    for line in reversed(lines):
+        if line.strip().startswith(msg):
+            return True
+    return False
+
+
+@pytest.mark.parametrize('use_datalad', ['off', 'on'])
+def test_conf_init(monkeypatch, tmp_path, use_datalad):
+    """Check the correct functioning of config set-up."""
+    home = (tmp_path / f'conf-init-{use_datalad}').resolve()
+    monkeypatch.setenv('TEMPLATEFLOW_USE_DATALAD', use_datalad)
+    monkeypatch.setenv('TEMPLATEFLOW_HOME', str(home))
+
+    # First execution, the S3 stub is created (or datalad install)
+    reload(tfc)
+    assert tfc.TF_CACHED is False
+    assert str(tfc.TF_HOME) == str(home)
+
+    reload(tfc)
+    assert tfc.TF_CACHED is True
+    assert str(tfc.TF_HOME) == str(home)
+
+
+@pytest.mark.parametrize('use_datalad', ['on', 'off'])
+def test_setup_home(monkeypatch, tmp_path, capsys, use_datalad):
+    """Check the correct functioning of the installation hook."""
+
+    if use_datalad == 'on':
+        # ImportError if not installed
+        pass
+
+    home = (tmp_path / f'setup-home-{use_datalad}').absolute()
+    monkeypatch.setenv('TEMPLATEFLOW_USE_DATALAD', use_datalad)
+    monkeypatch.setenv('TEMPLATEFLOW_HOME', str(home))
+
+    use_post = tfc._env_to_bool('TEMPLATEFLOW_USE_DATALAD', False)
+    assert use_post is (use_datalad == 'on')
+
+    with capsys.disabled():
+        reload(tfc)
+
+    # Ensure mocks are up-to-date
+    assert tfc.TF_USE_DATALAD is (use_datalad == 'on')
+    assert str(tfc.TF_HOME) == str(home)
+    # First execution, the S3 stub is created (or datalad install)
+    assert tfc.TF_CACHED is False
+    assert tfc.setup_home() is False
+
+    out = capsys.readouterr().out
+    assert _find_message(out, 'TemplateFlow was not cached')
+    assert (f'TEMPLATEFLOW_HOME={home}') in out
+    assert home.exists()
+    assert len(list(home.iterdir())) > 0
+
+    updated = tfc.setup_home(force=True)  # Templateflow is now cached
+    out = capsys.readouterr()[0]
+    assert _find_message(out, 'TemplateFlow was not cached') is False
+
+    if use_datalad == 'on':
+        assert _find_message(out, 'Updating TEMPLATEFLOW_HOME using DataLad')
+        assert updated is True
+
+    elif use_datalad == 'off':
+        # At this point, S3 should be up-to-date
+        assert updated is False
+        assert _find_message(out, 'TEMPLATEFLOW_HOME directory (S3 type) was up-to-date.')
+
+        # Let's force an update
+        rmtree(str(home / 'tpl-MNI152NLin2009cAsym'))
+        updated = tfc.setup_home(force=True)
+        out = capsys.readouterr()[0]
+        assert updated is True
+        assert _find_message(out, 'Updating TEMPLATEFLOW_HOME using S3.')
+
+    reload(tfc)
+    assert tfc.TF_CACHED is True
+    updated = tfc.setup_home()  # Templateflow is now cached
+    out = capsys.readouterr()[0]
+    assert not _find_message(out, 'TemplateFlow was not cached')
+
+    if use_datalad == 'on':
+        assert _find_message(out, 'Updating TEMPLATEFLOW_HOME using DataLad')
+        assert updated is True
+
+    elif use_datalad == 'off':
+        # At this point, S3 should be up-to-date
+        assert updated is False
+        assert _find_message(out, 'TEMPLATEFLOW_HOME directory (S3 type) was up-to-date.')
+
+        # Let's force an update
+        rmtree(str(home / 'tpl-MNI152NLin2009cAsym'))
+        updated = tfc.setup_home()
+        out = capsys.readouterr()[0]
+        assert updated is True
+        assert _find_message(out, 'Updating TEMPLATEFLOW_HOME using S3.')
+
+
+def test_layout(monkeypatch, tmp_path):
+    monkeypatch.setenv('TEMPLATEFLOW_USE_DATALAD', 'off')
+
+    lines = (f'{tfc.TF_LAYOUT}').splitlines()
+    assert lines[0] == 'TemplateFlow Layout'
+    assert lines[1] == f' - Home: {tfc.TF_HOME}'
+    assert lines[2].startswith(' - Templates:')
+
+
+def test_layout_errors(monkeypatch):
+    """Check regression of #71."""
+    import builtins
+    import sys
+    from importlib import __import__ as oldimport
+
+    @tfc.requires_layout
+    def myfunc():
+        return 'okay'
+
+    def mock_import(name, globals=None, locals=None, fromlist=(), level=0):  # noqa: A002
+        if name == 'bids':
+            raise ModuleNotFoundError
+        return oldimport(name, globals=globals, locals=locals, fromlist=fromlist, level=level)
+
+    with monkeypatch.context() as m:
+        m.setattr(tfc, 'TF_LAYOUT', None)
+        with pytest.raises(RuntimeError):
+            myfunc()
+
+        m.delitem(sys.modules, 'bids')
+        m.setattr(builtins, '__import__', mock_import)
+        with pytest.raises(ImportError):
+            myfunc()
diff --git a/templateflow/tests/test_s3.py b/templateflow/tests/test_s3.py
new file mode 100644
index 00000000..e8984438
--- /dev/null
+++ b/templateflow/tests/test_s3.py
@@ -0,0 +1,89 @@
+# emacs: -*- mode: python; py-indent-offset: 4; indent-tabs-mode: nil -*-
+# vi: set ft=python sts=4 ts=4 sw=4 et:
+#
+# Copyright 2024 The NiPreps Developers <nipreps@gmail.com>
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+# We support and encourage derived works from this project, please read
+# about our expectations at
+#
+#     https://www.nipreps.org/community/licensing/
+#
+"""Check S3-type repo tooling."""
+
+from importlib import reload
+from pathlib import Path
+
+import requests
+
+from templateflow import conf as tfc
+
+
+def test_get_skel_file(tmp_path, monkeypatch):
+    """Exercise the skeleton file generation."""
+
+    home = (tmp_path / 's3-skel-file').resolve()
+    monkeypatch.setenv('TEMPLATEFLOW_USE_DATALAD', 'off')
+    monkeypatch.setenv('TEMPLATEFLOW_HOME', str(home))
+
+    # First execution, the S3 stub is created (or datalad install)
+    reload(tfc)
+
+    local_md5 = tfc._s3.TF_SKEL_MD5
+    monkeypatch.setattr(tfc._s3, 'TF_SKEL_MD5', 'invent')
+    new_skel = tfc._s3._get_skeleton_file()
+    assert new_skel is not None
+    assert Path(new_skel).exists()
+    assert Path(new_skel).stat().st_size > 0
+
+    latest_md5 = (
+        requests.get(
+            tfc._s3.TF_SKEL_URL(release='master', ext='md5', allow_redirects=True), timeout=10
+        )
+        .content.decode()
+        .split()[0]
+    )
+    monkeypatch.setattr(tfc._s3, 'TF_SKEL_MD5', latest_md5)
+    assert tfc._s3._get_skeleton_file() is None
+
+    monkeypatch.setattr(tfc._s3, 'TF_SKEL_MD5', local_md5)
+    monkeypatch.setattr(tfc._s3, 'TF_SKEL_URL', 'http://weird/{release}/{ext}'.format)
+    assert tfc._s3._get_skeleton_file() is None
+
+    monkeypatch.setattr(
+        tfc._s3, 'TF_SKEL_URL', tfc._s3.TF_SKEL_URL(release='{release}', ext='{ext}z').format
+    )
+    assert tfc._s3._get_skeleton_file() is None
+
+
+def test_update_s3(tmp_path, monkeypatch):
+    """Exercise updating the S3 skeleton."""
+
+    newhome = (tmp_path / 's3-update').resolve()
+    monkeypatch.setenv('TEMPLATEFLOW_USE_DATALAD', 'off')
+    monkeypatch.setenv('TEMPLATEFLOW_HOME', str(newhome))
+
+    assert tfc._s3.update(newhome)
+    assert not tfc._s3.update(newhome, overwrite=False)
+    for p in (newhome / 'tpl-MNI152NLin6Sym').glob('*.nii.gz'):
+        p.unlink()
+    assert tfc._s3.update(newhome, overwrite=False)
+
+    # This should cover the remote zip file fetching
+    monkeypatch.setattr(tfc._s3, 'TF_SKEL_MD5', 'invent')
+    assert tfc._s3.update(newhome, local=False)
+    assert not tfc._s3.update(newhome, local=False, overwrite=False)
+    for p in (newhome / 'tpl-MNI152NLin6Sym').glob('*.nii.gz'):
+        p.unlink()
+    assert tfc._s3.update(newhome, local=False, overwrite=False)
diff --git a/templateflow/tests/test_version.py b/templateflow/tests/test_version.py
index e7178f40..d0a8df6c 100644
--- a/templateflow/tests/test_version.py
+++ b/templateflow/tests/test_version.py
@@ -21,6 +21,7 @@
 #     https://www.nipreps.org/community/licensing/
 #
 """Test version retrieval."""
+
 import sys
 from importlib import reload
 from importlib.metadata import PackageNotFoundError