diff --git a/.cruft.json b/.cruft.json
index 81bf4bd..6e9b169 100644
--- a/.cruft.json
+++ b/.cruft.json
@@ -1,6 +1,6 @@
 {
   "template": "https://github.com/sphinx-notes/cookiecutter",
-  "commit": "634c4022e575bd086ea47f3b42feafe24e14a939",
+  "commit": "62cd96195962da3392cdc34125c95e9144a5f5ca",
   "checkout": null,
   "context": {
     "cookiecutter": {
@@ -20,7 +20,7 @@
       "sphinx_version": "7.0",
       "development_status": "3 - Alpha",
       "_template": "https://github.com/sphinx-notes/cookiecutter",
-      "_commit": "634c4022e575bd086ea47f3b42feafe24e14a939"
+      "_commit": "62cd96195962da3392cdc34125c95e9144a5f5ca"
     }
   },
   "directory": null
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 638156d..7f56f2c 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -12,5 +12,14 @@ jobs:
     - uses: actions/setup-python@v5
       with:
         python-version-file: 'pyproject.toml'
-    - run: python3 -m pip install .[dev]
+    - run: python3 -m pip install .[test]
     - run: make test
+  doctest:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - uses: actions/setup-python@v5
+      with:
+        python-version-file: 'pyproject.toml'
+    - run: python3 -m pip install .[docs]
+    - run: make doctest
diff --git a/Makefile b/Makefile
index 06a9e9d..6e7539a 100644
--- a/Makefile
+++ b/Makefile
@@ -27,7 +27,11 @@ fmt:
 
 .PHONY: test
 test:
-	$(PY) -m unittest discover -s tests -v
+	$(PY) -m pytest tests/ -v
+
+.PHONY: doctest
+doctest:
+	$(MAKE) doctest -C docs/
 
 ################################################################################
 # Distribution Package
diff --git a/docs/conf.py b/docs/conf.py
index 3f6f141..2052dd2 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -23,6 +23,7 @@
 # ones.
 extensions = [
     'sphinx.ext.githubpages',
+    'sphinx.ext.doctest',
     'sphinx_design',
     'sphinx_copybutton',
     'sphinx_last_updated_by_git',
diff --git a/tests/conftest.py b/tests/conftest.py
new file mode 100644
index 0000000..b1ec9f9
--- /dev/null
+++ b/tests/conftest.py
@@ -0,0 +1,8 @@
+from pathlib import Path
+import pytest
+
+pytest_plugins = 'sphinx.testing.fixtures'
+
+@pytest.fixture(scope='session')
+def rootdir() -> Path:
+    return Path(__file__).parent / 'roots'
diff --git a/tests/roots/test-smoke/conf.py b/tests/roots/test-smoke/conf.py
new file mode 100644
index 0000000..319b202
--- /dev/null
+++ b/tests/roots/test-smoke/conf.py
@@ -0,0 +1 @@
+extensions = ['sphinxnotes.data']
diff --git a/tests/roots/test-smoke/index.rst b/tests/roots/test-smoke/index.rst
new file mode 100644
index 0000000..52d3541
--- /dev/null
+++ b/tests/roots/test-smoke/index.rst
@@ -0,0 +1,15 @@
+Smoke Test
+==========
+
+.. data:template::
+
+   Name: **{{ name }}**
+   {% for k, v in attrs.items() %}
+   {{ k }}: {{ v }}
+   {% endfor %}
+
+.. data:define:: Test User
+   :homepage: https://example.com/
+   :email: test@example.com
+
+   This is a test user.
diff --git a/tests/test_always_pass.py b/tests/test_always_pass.py
new file mode 100644
index 0000000..9a05eb7
--- /dev/null
+++ b/tests/test_always_pass.py
@@ -0,0 +1,9 @@
+# This file is generated from sphinx-notes/cookiecutter.
+# DO NOT EDIT.
+
+import unittest
+
+
+class TestAlwaysPass(unittest.TestCase):
+    def test_dummy(self):
+        self.assertTrue(True)
diff --git a/tests/test_smoke.py b/tests/test_smoke.py
new file mode 100644
index 0000000..6652f10
--- /dev/null
+++ b/tests/test_smoke.py
@@ -0,0 +1,27 @@
+"""Smoke tests for sphinxnotes.data extension."""
+
+import pytest
+
+PHASES = ['parsing', 'parsed', 'resolving']
+
+
+@pytest.mark.sphinx('html', testroot='smoke')
+@pytest.mark.parametrize('phase', PHASES)
+def test_data_template_and_define(app, status, warning, phase):
+    """Test that data:template and data:define directives work correctly."""
+    index_path = app.srcdir / 'index.rst'
+    content = index_path.read_text(encoding='utf-8')
+    modified_content = content.replace(
+        '.. data:template::',
+        f'.. data:template::\n   :on: {phase}',
+        1,
+    )
+    index_path.write_text(modified_content, encoding='utf-8')
+
+    app.build()
+
+    html = (app.outdir / 'index.html').read_text(encoding='utf-8')
+
+    assert 'Test User' in html
+    assert 'https://example.com/' in html
+    assert 'test%40example.com' in html