Make sure confirmation/danger banners have a H1

This makes errors on all pages have a `<h1>` element, which is important
for accessibility. It means a bit of rewriting the messages, but I think
they’re better for it.

app/main/views/templates.py

@@ -428,22 +428,24 @@ def delete_service_template(service_id, template_id):
         last_used_notification = template_statistics_client.get_template_statistics_for_template(
             service_id, template['id']
         )
-        message = '{} was last used {} ago'.format(
-            last_used_notification['template']['name'],
+        message = 'It was last used {} ago.'.format(
             get_human_readable_delta(
                 parse(last_used_notification['created_at']).replace(tzinfo=None),
-                datetime.utcnow())
+                datetime.utcnow()
+            )
         )
     except HTTPError as e:
         if e.status_code == 404:
-            message = '{} has never been used'.format(template['name'])
+            message = 'It’s never been used.'.format(template['name'])
         else:
             raise e
 
-    flash('{}. Are you sure you want to delete it?'.format(message), 'delete')
-
     return render_template(
         'views/templates/template.html',
+        template_delete_confirmation_message=(
+            'Are you sure you want to delete {}?'.format(template['name']),
+            message,
+        ),
         template=get_template(
             template,
             current_service,

app/templates/components/banner.html

@@ -7,7 +7,7 @@
     {% endif %}
   >
     {% if subhead -%}
-        {{ subhead }} 
+      <h1 class="banner-title">{{ subhead }}</h1>
     {%- endif -%}
     {{ body }}
     {% if delete_button %}

app/templates/views/templates/template.html

@@ -29,6 +29,20 @@
     </div>
   {% endif %}
 
+  {% if template_delete_confirmation_message %}
+    <div class="bottom-gutter">
+      {% call banner_wrapper(type='dangerous', subhead=template_delete_confirmation_message[0]) %}
+        <p>
+          {{ template_delete_confirmation_message[1] }}
+        </p>
+        <form method='post'>
+          <input type="hidden" name="csrf_token" value="{{ csrf_token() }}" />
+          <input type="submit" class="button" name="delete" value="Confirm" />
+        </form>
+      {% endcall %}
+    </div>
+  {% endif %}
+
   <h1 class="heading-large">{{ template.name }}</h1>
 
   <div class="grid-row">

tests/app/main/views/test_templates.py

@@ -679,16 +679,10 @@ def test_should_redirect_when_saving_a_template_email(
 
 
 def test_should_show_delete_template_page_with_time_block(
-    logged_in_client,
-    api_user_active,
-    mock_login,
-    mock_get_service,
+    client_request,
     mock_get_service_template,
-    mock_get_user,
-    mock_get_user_by_email,
-    mock_has_permissions,
-    fake_uuid,
     mocker,
+    fake_uuid
 ):
     with freeze_time('2012-01-01 12:00:00'):
         template = template_json('1234', '1234', "Test template", "sms", "Something very interesting")
@@ -698,30 +692,25 @@ def test_should_show_delete_template_page_with_time_block(
                      return_value=notification)
 
     with freeze_time('2012-01-01 12:10:00'):
-        service_id = fake_uuid
-        template_id = fake_uuid
-        response = logged_in_client.get(url_for(
+        page = client_request.get(
             '.delete_service_template',
-            service_id=service_id,
-            template_id=template_id))
-    content = response.get_data(as_text=True)
-    assert response.status_code == 200
-    assert 'Test template was last used 10 minutes ago. Are you sure you want to delete it?' in content
-    assert 'Are you sure' in content
-    assert 'Two week reminder' in content
-    assert 'Template <em>content</em> with & entity' in content
-    mock_get_service_template.assert_called_with(service_id, template_id)
+            service_id=SERVICE_ONE_ID,
+            template_id=fake_uuid,
+            _test_page_title=False,
+        )
+    assert page.h1.text == 'Are you sure you want to delete Two week reminder?'
+    assert normalize_spaces(page.select('.banner-dangerous p')[0].text) == (
+        'It was last used 10 minutes ago.'
+    )
+    assert normalize_spaces(page.select('.sms-message-wrapper')[0].text) == (
+        'service one: Template <em>content</em> with & entity'
+    )
+    mock_get_service_template.assert_called_with(SERVICE_ONE_ID, fake_uuid)
 
 
 def test_should_show_delete_template_page_with_never_used_block(
-    logged_in_client,
-    api_user_active,
-    mock_login,
-    mock_get_service,
+    client_request,
     mock_get_service_template,
-    mock_get_user,
-    mock_get_user_by_email,
-    mock_has_permissions,
     fake_uuid,
     mocker,
 ):
@@ -729,20 +718,20 @@ def test_should_show_delete_template_page_with_never_used_block(
         'app.template_statistics_client.get_template_statistics_for_template',
         side_effect=HTTPError(response=Mock(status_code=404), message="Default message")
     )
-    service_id = fake_uuid
-    template_id = fake_uuid
-    response = logged_in_client.get(url_for(
+    page = client_request.get(
         '.delete_service_template',
-        service_id=service_id,
-        template_id=template_id))
-
-    content = response.get_data(as_text=True)
-    assert response.status_code == 200
-    assert 'Two week reminder has never been used. Are you sure you want to delete it?' in content
-    assert 'Are you sure' in content
-    assert 'Two week reminder' in content
-    assert 'Template &lt;em&gt;content&lt;/em&gt; with &amp; entity' in content
-    mock_get_service_template.assert_called_with(service_id, template_id)
+        service_id=SERVICE_ONE_ID,
+        template_id=fake_uuid,
+        _test_page_title=False,
+    )
+    assert page.h1.text == 'Are you sure you want to delete Two week reminder?'
+    assert normalize_spaces(page.select('.banner-dangerous p')[0].text) == (
+        'It’s never been used.'
+    )
+    assert normalize_spaces(page.select('.sms-message-wrapper')[0].text) == (
+        'service one: Template <em>content</em> with & entity'
+    )
+    mock_get_service_template.assert_called_with(SERVICE_ONE_ID, fake_uuid)
 
 
 def test_should_redirect_when_deleting_a_template(
@@ -1094,6 +1083,7 @@ def test_should_show_message_before_redacting_template(
         'main.redact_template',
         service_id=SERVICE_ONE_ID,
         template_id=fake_uuid,
+        _test_page_title=False,
     )
 
     assert (