Let users select electoral wards of local authorities

If a library has groups, we should show a link instead of selecting the
group directly.

Then we can give the user the choice of selecting the whole of that
group, or specific areas within the group.

For now the only libraries we have with groups are local authorities,
which group electoral wards.

tests/app/main/views/test_broadcast.py

@@ -1,5 +1,6 @@
 import json
 import uuid
+from functools import partial
 
 import pytest
 from flask import url_for
@@ -257,12 +258,104 @@ def test_choose_broadcast_area_page(
     fake_uuid,
 ):
     service_one['permissions'] += ['broadcast']
-    client_request.get(
+    page = client_request.get(
         '.choose_broadcast_area',
         service_id=SERVICE_ONE_ID,
         broadcast_message_id=fake_uuid,
         library_slug='countries',
     )
+    assert [
+        (
+            choice.select_one('input')['value'],
+            normalize_spaces(choice.select_one('label').text),
+        )
+        for choice in page.select('form[method=post] .govuk-checkboxes__item')
+    ] == [
+        ('countries-E92000001', 'England'),
+        ('countries-N92000002', 'Northern Ireland'),
+        ('countries-S92000003', 'Scotland'),
+        ('countries-W92000004', 'Wales'),
+    ]
+
+
+def test_choose_broadcast_area_page_for_area_with_sub_areas(
+    client_request,
+    service_one,
+    mock_get_draft_broadcast_message,
+    fake_uuid,
+):
+    service_one['permissions'] += ['broadcast']
+    page = client_request.get(
+        '.choose_broadcast_area',
+        service_id=SERVICE_ONE_ID,
+        broadcast_message_id=fake_uuid,
+        library_slug='electoral-wards-of-the-united-kingdom',
+    )
+    partial_url_for = partial(
+        url_for,
+        'main.choose_broadcast_sub_area',
+        service_id=SERVICE_ONE_ID,
+        broadcast_message_id=fake_uuid,
+        library_slug='electoral-wards-of-the-united-kingdom',
+    )
+    choices = [
+        (
+            choice.select_one('a.file-list-filename-large')['href'],
+            normalize_spaces(choice.text),
+        )
+        for choice in page.select('.file-list-item')
+    ]
+    assert len(choices) == 379
+    assert choices[:2] == [
+        (
+            partial_url_for(area_slug='electoral-wards-of-the-united-kingdom-S12000033'),
+            'Aberdeen City',
+        ),
+        (
+            partial_url_for(area_slug='electoral-wards-of-the-united-kingdom-S12000034'),
+            'Aberdeenshire',
+        ),
+    ]
+    assert choices[-1:] == [
+        (
+            partial_url_for(area_slug='electoral-wards-of-the-united-kingdom-E06000014'),
+            'York',
+        ),
+    ]
+
+
+def test_choose_broadcast_sub_area_page(
+    client_request,
+    service_one,
+    mock_get_draft_broadcast_message,
+    fake_uuid,
+):
+    service_one['permissions'] += ['broadcast']
+    page = client_request.get(
+        'main.choose_broadcast_sub_area',
+        service_id=SERVICE_ONE_ID,
+        broadcast_message_id=fake_uuid,
+        library_slug='electoral-wards-of-the-united-kingdom',
+        area_slug='electoral-wards-of-the-united-kingdom-S12000033',
+    )
+    assert normalize_spaces(page.select_one('h1').text) == (
+        'Choose an area of Aberdeen City'
+    )
+    choices = [
+        (
+            choice.select_one('input')['value'],
+            normalize_spaces(choice.select_one('label').text),
+        )
+        for choice in page.select('form[method=post] .govuk-checkboxes__item')
+    ]
+    assert choices[:3] == [
+        ('y', 'All of Aberdeen City'),
+        ('electoral-wards-of-the-united-kingdom-S13002845', 'Airyhall/Broomhill/Garthdee'),
+        ('electoral-wards-of-the-united-kingdom-S13002836', 'Bridge of Don'),
+    ]
+    assert choices[-1:] == [
+        ('electoral-wards-of-the-united-kingdom-S13002846', 'Torry/Ferryhill'),
+    ]
 
 
 def test_add_broadcast_area(
@@ -291,6 +384,57 @@ def test_add_broadcast_area(
     )
 
 
+@pytest.mark.parametrize('post_data, expected_selected', (
+    ({
+        'select_all': 'y',
+        'areas': [
+            'electoral-wards-of-the-united-kingdom-S13002845',
+        ]
+    }, [
+        'electoral-wards-of-the-united-kingdom-S12000033',
+        # S13002845 is ignored because the user chose ‘Select all…’
+    ]),
+    ({
+        'areas': [
+            'electoral-wards-of-the-united-kingdom-S13002845',
+            'electoral-wards-of-the-united-kingdom-S13002836',
+        ]
+    }, [
+        'electoral-wards-of-the-united-kingdom-S13002845',
+        'electoral-wards-of-the-united-kingdom-S13002836',
+    ]),
+))
+def test_add_broadcast_sub_area(
+    client_request,
+    service_one,
+    mock_get_draft_broadcast_message,
+    mock_update_broadcast_message,
+    fake_uuid,
+    post_data,
+    expected_selected,
+):
+    service_one['permissions'] += ['broadcast']
+    client_request.post(
+        '.choose_broadcast_sub_area',
+        service_id=SERVICE_ONE_ID,
+        broadcast_message_id=fake_uuid,
+        library_slug='countries',
+        area_slug='electoral-wards-of-the-united-kingdom-S12000033',
+        _data=post_data,
+    )
+    mock_update_broadcast_message.assert_called_once_with(
+        service_id=SERVICE_ONE_ID,
+        broadcast_message_id=fake_uuid,
+        data={
+            'areas': [
+                # These two areas are on the broadcast already
+                'countries-E92000001',
+                'countries-S92000003',
+            ] + expected_selected
+        },
+    )
+
+
 def test_remove_broadcast_area_page(
     client_request,
     service_one,