tests: Add tests for deprecation warnings

tests/fixtures/deprecation_warning_hook_return/copier.yml

@@ -0,0 +1,3 @@
+_jinja_extensions:
+- copier_templates_extensions.TemplateExtensionLoader
+- extensions.py:ContextUpdater

tests/fixtures/deprecation_warning_hook_return/extensions.py

@@ -0,0 +1,6 @@
+from copier_templates_extensions import ContextHook
+
+
+class ContextUpdater(ContextHook):
+    def hook(self, context):
+        return {"success": True}

tests/fixtures/deprecation_warning_hook_return/result.txt.jinja

@@ -0,0 +1 @@
+Success variable: {{ success|default("not set") }}

tests/fixtures/deprecation_warning_update_attr/copier.yml

@@ -0,0 +1,3 @@
+_jinja_extensions:
+- copier_templates_extensions.TemplateExtensionLoader
+- extensions.py:ContextUpdater

tests/fixtures/deprecation_warning_update_attr/extensions.py

@@ -0,0 +1,8 @@
+from copier_templates_extensions import ContextHook
+
+
+class ContextUpdater(ContextHook):
+    update = "not sentinel"
+
+    def hook(self, context):
+        context["success"] = True

tests/fixtures/deprecation_warning_update_attr/result.txt.jinja

@@ -0,0 +1 @@
+Success variable: {{ success|default("not set") }}

tests/test_extensions.py

@@ -58,3 +58,22 @@ def test_extensions_raising_exceptions(tmp_path: Path, template_name: str, excep
         copier.run_copy(str(template_path), tmp_path, defaults=True, overwrite=True, unsafe=True)
     assert not (tmp_path / "result.txt").exists()
     assert not (tmp_path / "extensions.py").exists()
+
+
+@pytest.mark.parametrize(
+    "template_name",
+    ["deprecation_warning_hook_return", "deprecation_warning_update_attr"],
+)
+def test_deprecated_usage(tmp_path: Path, template_name: str) -> None:
+    """Test deprecation warnings.
+
+    Arguments:
+        tmp_path: A pytest fixture.
+        template_name: The parametrized template to use.
+    """
+    template_path = TEMPLATES_DIRECTORY / template_name
+    with pytest.warns(DeprecationWarning):
+        copier.run_copy(str(template_path), tmp_path, defaults=True, overwrite=True, unsafe=True)
+    result_file = tmp_path / "result.txt"
+    assert result_file.exists()
+    assert result_file.read_text() == "Success variable: True"