Refs #34488 -- Made ClearableFileInput preserve "Clear" checked attribute when form is invalid.

tests/forms_tests/widget_tests/test_clearablefileinput.py

@@ -111,6 +111,21 @@ class ClearableFileInputTest(WidgetTest):
             ),
         )
 
+    def test_render_checked(self):
+        self.widget.checked = True
+        self.check_html(
+            self.widget,
+            "myfile",
+            FakeFieldFile(),
+            html=(
+                'Currently: <a href="something">something</a>'
+                '<input type="checkbox" name="myfile-clear" id="myfile-clear_id" '
+                "checked>"
+                '<label for="myfile-clear_id">Clear</label><br>Change: '
+                '<input type="file" name="myfile" checked>'
+            ),
+        )
+
     def test_render_no_disabled(self):
         class TestForm(Form):
             clearable_file = FileField(