corrected a very foolish oversight in bootstrap error class handling that sought .is-valid instead of .is-invalid; now FTs 'pass'—up until return line only, in the case of functional_tests.test_list_item_validation

src/templates/core/base.html

@@ -21,7 +21,7 @@
                         <input
                             name="item_text"
                             id="id-new-item"
-                            class="form-control form-control-lg {% if error %}is-valid{% endif %}"
+                            class="form-control form-control-lg {% if error %}is-invalid{% endif %}"
                             placeholder="Enter a to-do item"
                         />
                         {% csrf_token %}