Fix tests around jinja2 (readthedocs#9050)

Author: ericholscher

readthedocs/projects/tests/test_build_tasks.py

@@ -524,6 +524,7 @@ def test_build_commands_executed(self, load_yaml_config):
                     "sphinx<2",
                     "sphinx-rtd-theme<0.5",
                     "readthedocs-sphinx-ext<2.2",
+                    "jinja2<3.1.0",
                     bin_path=mock.ANY,
                     cwd=mock.ANY,
                 ),

readthedocs/rtd_tests/tests/test_doc_building.py

@@ -1,7 +1,7 @@
-from itertools import zip_longest
 import os
 import tempfile
 import uuid
+from itertools import zip_longest
 from unittest import mock
 from unittest.mock import Mock, PropertyMock, patch
 
@@ -407,11 +407,12 @@ def test_install_core_requirements_sphinx(self, checkout_path):
         )
         python_env.install_core_requirements()
         requirements_sphinx = [
-            'commonmark',
-            'recommonmark',
-            'sphinx',
-            'sphinx-rtd-theme',
-            'readthedocs-sphinx-ext',
+            "commonmark",
+            "recommonmark",
+            "sphinx",
+            "sphinx-rtd-theme",
+            "readthedocs-sphinx-ext",
+            "jinja2<3.1.0",
         ]
 
         self.assertEqual(self.build_env_mock.run.call_count, 2)
@@ -444,12 +445,13 @@ def test_install_core_requirements_sphinx_system_packages_caps_setuptools(self,
         )
         python_env.install_core_requirements()
         requirements_sphinx = [
-            'commonmark',
-            'recommonmark',
-            'sphinx',
-            'sphinx-rtd-theme',
-            'readthedocs-sphinx-ext',
-            'setuptools<58.3.0',
+            "commonmark",
+            "recommonmark",
+            "sphinx",
+            "sphinx-rtd-theme",
+            "readthedocs-sphinx-ext",
+            "jinja2<3.1.0",
+            "setuptools<58.3.0",
         ]
 
         self.assertEqual(self.build_env_mock.run.call_count, 2)