update chapter with the failing validation FT

Author: Xronophobe

chapter_15_advanced_forms.asciidoc

@@ -774,7 +774,7 @@ NOTE: Personal opinion here: I could have used `super`, but I prefer not to use
     Anything else is too error-prone, and I find it ugly besides. YMMV.
 
 
-And we're there!  All the unit tests pass:
+Let's run the tests!  All the unit tests pass:
 
 [subs="specialcharacters,macros"]
 ----
@@ -785,7 +785,67 @@ Ran 30 tests in 0.082s
 OK
 ----
 
-And so does our FT for validation:
+But we still have something to do about our FTs:
+[subs="specialcharacters,macros"]
+----
+$ pass:quotes[*python manage.py test functional_tests.test_list_item_validation*]
+[...]
+FAIL: test_cannot_add_duplicate_items (functional_tests.test_list_item_validation.ItemValidationTest.test_cannot_add_duplicate_items)
+----------------------------------------------------------------------
+[...]
+AssertionError: '' != "You've already got this in your list"
++ You've already got this in your list
+----
+
+The error message isn't being displayed because we are not using the Bootstrap
+classes. Although it would have been nice to minimise hand-written html and
+utilise Django instead, it seems like we need to bring back our custom
+`<input>` and add a few attributes manually:
+
+[role="sourcecode"]
+.src/lists/templates/base.html
+====
+[source,diff]
+----
+@@ -13,13 -14,26 +14,26 @@@
+  <div class="col-lg-6 text-center">
+      <h1 class="display-1 mb-4">{% block header_text %}{% endblock %}</h1>
+-     <form method="POST" action="{% block form_action %}{% endblock %}">
+-         {{ form.text }}
++     <form
++         class="was-validated"  <1>
++         method="POST"
++         action="{% block form_action %}{% endblock %}"
++     >
+          {% csrf_token %}
++         <input
++             id="id_text"
++             name="text"
++             class="form-control form-control-lg {% if form.errors %}is-invalid{% endif %}"  <2>
++             placeholder="Enter a to-do item"
++             value="{{ form.text.value }}"
++             aria-describedby="id_text_feedback"
++             required
++         />
+          {% if form.errors %}
+-             <div class="invalid-feedback">{{ form.errors.text }}</div>
++             <div class="invalid-feedback">{{ form.errors.text.0 }}</div>  <3>
+          {% endif %}
+      </form>
+  </div>
+----
+====
+
+<1> We give `.was-validated` to the `<form>`
+<2> We provide an `<input>` and the most important custom setting will be its
+    `class`. As you can see, we can use conditionals even for providing
+    additional `class` -es.
+<3> If you try to just simply display `form.errors.text` you'll see it ends up
+    as a list item in an unordered list. To avoid that, let's just
+    select `form.errors.text.0`.
+
+
+Now when we run the FT for validation again:
 
 [subs="specialcharacters,macros"]
 ----
@@ -815,9 +875,6 @@ Hooray! Time for a final commit, and a wrap-up of what we've learned about
 testing views over the last few chapters.((("", startref="DITlist15")))
 
 
-
-
-
 === Wrapping Up: What We've Learned About Testing Django
 
 ((("class-based generic views (CBGVs)", "key tests and assertions")))((("Django framework", "class-based generic views")))We're