diff --git a/.github/workflows/j2cli.yml b/.github/workflows/j2cli.yml
index 1a74dfe..df5b863 100644
--- a/.github/workflows/j2cli.yml
+++ b/.github/workflows/j2cli.yml
@@ -1,3 +1,6 @@
+# Related documentation:
+#   https://jacobian.org/til/github-actions-poetry/
+#   https://github.com/snok/install-poetry
 name: m000/j2cli
 on:
   push:
@@ -9,28 +12,51 @@ concurrency:
   cancel-in-progress: true
 jobs:
   test:
-    runs-on: ubuntu-latest
-    env:
-      TOXENV: py3.10-pyyaml6
+    strategy:
+      fail-fast: true
+      matrix:
+        os: [ "ubuntu-latest" ]
+        python-version: [ "3.10", "3.11" ]
+    runs-on: ${{ matrix.os }}
+#   env:
+#     TOXENV: py${{ matrix.python-version }}-pyyaml6
     steps:
-    - uses: actions/checkout@v4.1.0
-    - uses: actions/setup-python@v4.7.0
+    - name: Repository checkout
+      uses: actions/checkout@v4
+    - name: Python ${{ matrix.python-version }} setup
+      uses: actions/setup-python@v4
       with:
-        python-version: "3.10"
-    - run: pip install tox
-    - run: tox
-  coverage:
-    runs-on: ubuntu-latest
-    env:
-      TOXENV: py3.10-pyyaml6
-    steps:
-    - uses: actions/checkout@v4.1.0
-    - uses: actions/setup-python@v4.7.0
+        python-version: ${{ matrix.python-version }}
+    - name: Load cached Poetry installation
+      id: cached-poetry
+      uses: actions/cache@v3
+      with:
+        path: ~/.local  # the path depends on the OS
+        key: poetry-0  # increment to reset cache
+    - name: Install Poetry
+      if: steps.cached-poetry.outputs.cache-hit != 'true'
+      uses: snok/install-poetry@v1
+      with:
+        version: 1.7.0
+        virtualenvs-create: true
+        virtualenvs-in-project: true  # create .venv in test directory
+    - name: Install Poetry development dependencies  # main dependencies are handled by tox
+      if: steps.cached-poetry.outputs.cache-hit != 'true'
+      run: poetry install --no-interaction --no-root --only=dev
+    - name: Load cached tox environment
+      id: cached-toxenv
+      uses: actions/cache@v3
       with:
-        python-version: "3.10"
-    - uses: orgoro/coverage@v3.1
+        path: .tox/py${{ matrix.python-version }}-**
+        key: toxenv-py${{ matrix.python-version }}-${{ hashFiles('tox.ini') }}
+    - name: Tox tests (py${{ matrix.python-version }})
+      run: poetry run tox
+    - name: Send coverage reports to Codecov
+      uses: codecov/codecov-action@v3
       with:
-        coverageFile: coverage.xml
-        token: ${{ secrets.GITHUB_TOKEN }}
-    - run: pip install tox
-    - run: tox
+        token: ${{ secrets.CODECOV_TOKEN }}
+        #files: ./coverage1.xml,./coverage2.xml # optional
+        #flags: unittests # optional
+        #name: codecov-umbrella # optional
+        fail_ci_if_error: false
+        verbose: true
diff --git a/poetry.lock b/poetry.lock
new file mode 100644
index 0000000..d1731d8
--- /dev/null
+++ b/poetry.lock
@@ -0,0 +1,376 @@
+# This file is automatically @generated by Poetry 1.7.0 and should not be changed by hand.
+
+[[package]]
+name = "cachetools"
+version = "5.3.2"
+description = "Extensible memoizing collections and decorators"
+optional = false
+python-versions = ">=3.7"
+files = [
+    {file = "cachetools-5.3.2-py3-none-any.whl", hash = "sha256:861f35a13a451f94e301ce2bec7cac63e881232ccce7ed67fab9b5df4d3beaa1"},
+    {file = "cachetools-5.3.2.tar.gz", hash = "sha256:086ee420196f7b2ab9ca2db2520aca326318b68fe5ba8bc4d49cca91add450f2"},
+]
+
+[[package]]
+name = "chardet"
+version = "5.2.0"
+description = "Universal encoding detector for Python 3"
+optional = false
+python-versions = ">=3.7"
+files = [
+    {file = "chardet-5.2.0-py3-none-any.whl", hash = "sha256:e1cf59446890a00105fe7b7912492ea04b6e6f06d4b742b2c788469e34c82970"},
+    {file = "chardet-5.2.0.tar.gz", hash = "sha256:1b3b6ff479a8c414bc3fa2c0852995695c4a026dcd6d0633b2dd092ca39c1cf7"},
+]
+
+[[package]]
+name = "colorama"
+version = "0.4.6"
+description = "Cross-platform colored terminal text."
+optional = false
+python-versions = "!=3.0.*,!=3.1.*,!=3.2.*,!=3.3.*,!=3.4.*,!=3.5.*,!=3.6.*,>=2.7"
+files = [
+    {file = "colorama-0.4.6-py2.py3-none-any.whl", hash = "sha256:4f1d9991f5acc0ca119f9d443620b77f9d6b33703e51011c16baf57afb285fc6"},
+    {file = "colorama-0.4.6.tar.gz", hash = "sha256:08695f5cb7ed6e0531a20572697297273c47b8cae5a63ffc6d6ed5c201be6e44"},
+]
+
+[[package]]
+name = "distlib"
+version = "0.3.7"
+description = "Distribution utilities"
+optional = false
+python-versions = "*"
+files = [
+    {file = "distlib-0.3.7-py2.py3-none-any.whl", hash = "sha256:2e24928bc811348f0feb63014e97aaae3037f2cf48712d51ae61df7fd6075057"},
+    {file = "distlib-0.3.7.tar.gz", hash = "sha256:9dafe54b34a028eafd95039d5e5d4851a13734540f1331060d31c9916e7147a8"},
+]
+
+[[package]]
+name = "exceptiongroup"
+version = "1.1.3"
+description = "Backport of PEP 654 (exception groups)"
+optional = false
+python-versions = ">=3.7"
+files = [
+    {file = "exceptiongroup-1.1.3-py3-none-any.whl", hash = "sha256:343280667a4585d195ca1cf9cef84a4e178c4b6cf2274caef9859782b567d5e3"},
+    {file = "exceptiongroup-1.1.3.tar.gz", hash = "sha256:097acd85d473d75af5bb98e41b61ff7fe35efe6675e4f9370ec6ec5126d160e9"},
+]
+
+[package.extras]
+test = ["pytest (>=6)"]
+
+[[package]]
+name = "filelock"
+version = "3.13.1"
+description = "A platform independent file lock."
+optional = false
+python-versions = ">=3.8"
+files = [
+    {file = "filelock-3.13.1-py3-none-any.whl", hash = "sha256:57dbda9b35157b05fb3e58ee91448612eb674172fab98ee235ccb0b5bee19a1c"},
+    {file = "filelock-3.13.1.tar.gz", hash = "sha256:521f5f56c50f8426f5e03ad3b281b490a87ef15bc6c526f168290f0c7148d44e"},
+]
+
+[package.extras]
+docs = ["furo (>=2023.9.10)", "sphinx (>=7.2.6)", "sphinx-autodoc-typehints (>=1.24)"]
+testing = ["covdefaults (>=2.3)", "coverage (>=7.3.2)", "diff-cover (>=8)", "pytest (>=7.4.3)", "pytest-cov (>=4.1)", "pytest-mock (>=3.12)", "pytest-timeout (>=2.2)"]
+typing = ["typing-extensions (>=4.8)"]
+
+[[package]]
+name = "iniconfig"
+version = "2.0.0"
+description = "brain-dead simple config-ini parsing"
+optional = false
+python-versions = ">=3.7"
+files = [
+    {file = "iniconfig-2.0.0-py3-none-any.whl", hash = "sha256:b6a85871a79d2e3b22d2d1b94ac2824226a63c6b741c88f7ae975f18b6778374"},
+    {file = "iniconfig-2.0.0.tar.gz", hash = "sha256:2d91e135bf72d31a410b17c16da610a82cb55f6b0477d1a902134b24a455b8b3"},
+]
+
+[[package]]
+name = "jinja2"
+version = "3.1.2"
+description = "A very fast and expressive template engine."
+optional = false
+python-versions = ">=3.7"
+files = [
+    {file = "Jinja2-3.1.2-py3-none-any.whl", hash = "sha256:6088930bfe239f0e6710546ab9c19c9ef35e29792895fed6e6e31a023a182a61"},
+    {file = "Jinja2-3.1.2.tar.gz", hash = "sha256:31351a702a408a9e7595a8fc6150fc3f43bb6bf7e319770cbc0db9df9437e852"},
+]
+
+[package.dependencies]
+MarkupSafe = ">=2.0"
+
+[package.extras]
+i18n = ["Babel (>=2.7)"]
+
+[[package]]
+name = "markupsafe"
+version = "2.1.3"
+description = "Safely add untrusted strings to HTML/XML markup."
+optional = false
+python-versions = ">=3.7"
+files = [
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diff --git a/tests/requirements.txt b/tests/requirements.txt
deleted file mode 100644
index e079f8a..0000000
--- a/tests/requirements.txt
+++ /dev/null
@@ -1 +0,0 @@
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diff --git a/tox.ini b/tox.ini
index 352dd54..b0f04b2 100644
--- a/tox.ini
+++ b/tox.ini
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 [tox]
 envlist=
-    py{3.10}-pyyaml{0,6}
+    py{3.10, 3.11}-pyyaml{0,6}
 skip_missing_interpreters=True
 
 [testenv]
+# See: https://tox.wiki/en/latest/config.html#tox-ini
 basepython=
     py3.10: python3.10
+    py3.11: python3.11
 deps=
-    -rtests/requirements.txt
     pyyaml0: null
     pyyaml6: pyyaml~=6.0
-allowlist_externals = pytest
+allowlist_externals = poetry
 commands=
-    pytest {posargs:tests/}
+    poetry install --no-interaction
+    poetry run pytest {posargs:tests/}
+
+# NB: matrix should extrapolate to poetry with/without settings rather than specific versions
 
 #[testenv:lint]
 #basepython=
@@ -23,10 +27,7 @@ commands=
 #commands=
 #    prospector
 
-[testenv:dev]
-deps=
-    -rtest/requirements.txt
-usedevelop=True
-
-# To see how these expand to tests, see:
-#   https://tox.readthedocs.io/en/latest/example/basic.html#compressing-dependency-matrix
+#[testenv:dev]
+#deps=
+#-rtest/requirements.txt
+#usedevelop=True