django/tests/template_tests/test_extends.py

import os

from django.template import Context, Engine, TemplateDoesNotExist, TemplateSyntaxError
from django.test import SimpleTestCase

from .utils import ROOT, setup

RECURSIVE = os.path.join(ROOT, "recursive_templates")


class ExtendsBehaviorTests(SimpleTestCase):
    def test_normal_extend(self):
        engine = Engine(dirs=[os.path.join(RECURSIVE, "fs")])
        template = engine.get_template("one.html")
        output = template.render(Context({}))
        self.assertEqual(output.strip(), "three two one")

    def test_extend_recursive(self):
        engine = Engine(
            dirs=[
                os.path.join(RECURSIVE, "fs"),
                os.path.join(RECURSIVE, "fs2"),
                os.path.join(RECURSIVE, "fs3"),
            ]
        )
        template = engine.get_template("recursive.html")
        output = template.render(Context({}))
        self.assertEqual(output.strip(), "fs3/recursive fs2/recursive fs/recursive")

    def test_extend_missing(self):
        engine = Engine(dirs=[os.path.join(RECURSIVE, "fs")])
        template = engine.get_template("extend-missing.html")
        with self.assertRaises(TemplateDoesNotExist) as e:
            template.render(Context({}))

        tried = e.exception.tried
        self.assertEqual(len(tried), 1)
        self.assertEqual(tried[0][0].template_name, "missing.html")

    def test_recursive_multiple_loaders(self):
        engine = Engine(
            dirs=[os.path.join(RECURSIVE, "fs")],
            loaders=[
                (
                    "django.template.loaders.locmem.Loader",
                    {
                        "one.html": (
                            '{% extends "one.html" %}{% block content %}'
                            "{{ block.super }} locmem-one{% endblock %}"
                        ),
                        "two.html": (
                            '{% extends "two.html" %}{% block content %}'
                            "{{ block.super }} locmem-two{% endblock %}"
                        ),
                        "three.html": (
                            '{% extends "three.html" %}{% block content %}'
                            "{{ block.super }} locmem-three{% endblock %}"
                        ),
                    },
                ),
                "django.template.loaders.filesystem.Loader",
            ],
        )
        template = engine.get_template("one.html")
        output = template.render(Context({}))
        self.assertEqual(
            output.strip(), "three locmem-three two locmem-two one locmem-one"
        )

    def test_extend_self_error(self):
        """
        Catch if a template extends itself and no other matching
        templates are found.
        """
        engine = Engine(dirs=[os.path.join(RECURSIVE, "fs")])
        template = engine.get_template("self.html")
        with self.assertRaises(TemplateDoesNotExist) as e:
            template.render(Context({}))
        tried = e.exception.tried
        self.assertEqual(len(tried), 1)
        origin, message = tried[0]
        self.assertEqual(origin.template_name, "self.html")
        self.assertEqual(message, "Skipped to avoid recursion")

    def test_extend_cached(self):
        engine = Engine(
            dirs=[
                os.path.join(RECURSIVE, "fs"),
                os.path.join(RECURSIVE, "fs2"),
                os.path.join(RECURSIVE, "fs3"),
            ],
            loaders=[
                (
                    "django.template.loaders.cached.Loader",
                    [
                        "django.template.loaders.filesystem.Loader",
                    ],
                ),
            ],
        )
        template = engine.get_template("recursive.html")
        output = template.render(Context({}))
        self.assertEqual(output.strip(), "fs3/recursive fs2/recursive fs/recursive")

        cache = engine.template_loaders[0].get_template_cache
        self.assertEqual(len(cache), 3)
        expected_path = os.path.join("fs", "recursive.html")
        self.assertTrue(cache["recursive.html"].origin.name.endswith(expected_path))

        # Render another path that uses the same templates from the cache
        template = engine.get_template("other-recursive.html")
        output = template.render(Context({}))
        self.assertEqual(output.strip(), "fs3/recursive fs2/recursive fs/recursive")

        # Template objects should not be duplicated.
        self.assertEqual(len(cache), 4)
        expected_path = os.path.join("fs", "other-recursive.html")
        self.assertTrue(
            cache["other-recursive.html"].origin.name.endswith(expected_path)
        )

    def test_unique_history_per_loader(self):
        """
        Extending should continue even if two loaders return the same
        name for a template.
        """
        engine = Engine(
            loaders=[
                [
                    "django.template.loaders.locmem.Loader",
                    {
                        "base.html": (
                            '{% extends "base.html" %}{% block content %}'
                            "{{ block.super }} loader1{% endblock %}"
                        ),
                    },
                ],
                [
                    "django.template.loaders.locmem.Loader",
                    {
                        "base.html": "{% block content %}loader2{% endblock %}",
                    },
                ],
            ]
        )
        template = engine.get_template("base.html")
        output = template.render(Context({}))
        self.assertEqual(output.strip(), "loader2 loader1")

    def test_block_override_in_extended_included_template(self):
        """
        ExtendsNode.find_template() initializes history with self.origin
        (#28071).
        """
        engine = Engine(
            loaders=[
                [
                    "django.template.loaders.locmem.Loader",
                    {
                        "base.html": (
                            "{% extends 'base.html' %}{% block base %}{{ block.super }}"
                            "2{% endblock %}"
                        ),
                        "included.html": (
                            "{% extends 'included.html' %}{% block included %}"
                            "{{ block.super }}B{% endblock %}"
                        ),
                    },
                ],
                [
                    "django.template.loaders.locmem.Loader",
                    {
                        "base.html": (
                            "{% block base %}1{% endblock %}"
                            "{% include 'included.html' %}"
                        ),
                        "included.html": "{% block included %}A{% endblock %}",
                    },
                ],
            ],
        )
        template = engine.get_template("base.html")
        self.assertEqual(template.render(Context({})), "12AB")

    @setup(
        {"index.html": "{% block content %}B{% endblock %}{% extends 'base.html' %}"}
    )
    def test_extends_not_first_tag_in_extended_template(self):
        msg = "{% extends 'base.html' %} must be the first tag in 'index.html'."
        with self.assertRaisesMessage(TemplateSyntaxError, msg):
            self.engine.get_template("index.html")

    def test_extends_not_first_tag_in_extended_template_from_string(self):
        template_string = "{% block content %}B{% endblock %}{% extends 'base.html' %}"
        msg = "{% extends 'base.html' %} must be the first tag in the template."
        with self.assertRaisesMessage(TemplateSyntaxError, msg):
            Engine().from_string(template_string)