diff --git a/beangulp/tests/testing.rst b/beangulp/tests/testing.rst
index 180ab11..fab6354 100644
--- a/beangulp/tests/testing.rst
+++ b/beangulp/tests/testing.rst
@@ -27,8 +27,6 @@ Tests
 Check the basics:
 
   >>> r = run()
-  >>> r.exit_code
-  0
   >>> print(r.output)
   Usage: beangulp [OPTIONS] COMMAND [ARGS]...
 
diff --git a/pyproject.toml b/pyproject.toml
index 0ae3141..9595973 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -28,23 +28,31 @@ classifiers = [
     'Topic :: Office/Business :: Financial :: Accounting',
     'Topic :: Text Processing :: General',
 ]
-requires-python = ">=3.7"
+requires-python = '>=3.7'
 dependencies = [
-    "beancount>=2.3.5",
+    'beancount >=2.3.5',
     'beautifulsoup4',
     'chardet',
     'click >8.0',
-    "deprecation>=2.1.0", # Note: 3.13 provides warnings.deprecated().
+    'deprecation >=2.1.0', # Python 3.13 provides warnings.deprecated().
     'lxml',
-    "petl",
-    "pytest",
     'python-magic >=0.4.12; sys_platform != "win32"',
 ]
 
+[project.optional-dependencies]
+petl = [
+    'petl',
+]
+
 [project.urls]
 homepage = 'https://github.com/beancount/beangulp'
 issues = 'https://github.com/beancount/beangulp/issues'
 
+[dependency-groups]
+test = [
+    'pytest',
+]
+
 [tool.setuptools.packages]
 find = {}