Tell template preview whether a letter can be sent internationally

If a service has permission to send international letters then the admin
app should tell template preview, so that template preview knows what
rules to apply when it’s validating the address of the letter.

We don’t need to wait for template preview to start looking at this
query string argument – it will just ignore it for now.

tests/app/main/views/test_uploads.py

@@ -143,16 +143,22 @@ def test_get_upload_letter(client_request):
     assert normalize_spaces(page.find('label', class_='file-upload-button').text) == 'Choose file'
 
 
+@pytest.mark.parametrize('extra_permissions, expected_allow_international', (
+    ([], False),
+    (['international_letters'], True),
+))
 def test_post_upload_letter_redirects_for_valid_file(
     mocker,
     active_user_with_permissions,
     service_one,
     client_request,
     fake_uuid,
+    extra_permissions,
+    expected_allow_international,
 ):
     mocker.patch('uuid.uuid4', return_value=fake_uuid)
     antivirus_mock = mocker.patch('app.main.views.uploads.antivirus_client.scan', return_value=True)
-    mocker.patch(
+    mock_sanitise = mocker.patch(
         'app.main.views.uploads.sanitise_letter',
         return_value=Mock(
             content='The sanitised content',
@@ -169,6 +175,7 @@ def test_post_upload_letter_redirects_for_valid_file(
     mocker.patch('app.main.views.uploads.service_api_client.get_precompiled_template')
 
     service_one['restricted'] = False
+    service_one['permissions'] += extra_permissions
     client_request.login(active_user_with_permissions, service=service_one)
 
     with open('tests/test_pdf_files/one_page_pdf.pdf', 'rb') as file:
@@ -188,6 +195,10 @@ def test_post_upload_letter_redirects_for_valid_file(
         filename='tests/test_pdf_files/one_page_pdf.pdf',
         recipient='The Queen',
     )
+    mock_sanitise.assert_called_once_with(
+        ANY,
+        allow_international_letters=expected_allow_international,
+    )
 
     assert 'The Queen' in page.find('div', class_='js-stick-at-bottom-when-scrolling').text
     assert page.find('h1').text == 'tests/test_pdf_files/one_page_pdf.pdf'

tests/app/test_template_previews.py

@@ -164,13 +164,21 @@ def test_from_example_template_makes_request(mocker):
     )
 
 
-def test_sanitise_letter_calls_template_preview_sanitise_endoint_with_file(mocker):
+@pytest.mark.parametrize('allow_international_letters, expected_url', (
+    (False, 'http://localhost:9999/precompiled/sanitise?allow_international_letters=false'),
+    (True, 'http://localhost:9999/precompiled/sanitise?allow_international_letters=true'),
+))
+def test_sanitise_letter_calls_template_preview_sanitise_endoint_with_file(
+    mocker,
+    allow_international_letters,
+    expected_url,
+):
     request_mock = mocker.patch('app.template_previews.requests.post')
 
-    sanitise_letter('pdf_data')
+    sanitise_letter('pdf_data', allow_international_letters=allow_international_letters)
 
     request_mock.assert_called_once_with(
-        'http://localhost:9999/precompiled/sanitise',
+        expected_url,
         headers={'Authorization': 'Token my-secret-key'},
         data='pdf_data'
     )