Show all pages of a letter everywhere

Right now showing all the pages in full is the only way we have of
showing a letter that makes sense to our users. Maybe in the future we
show some kind of truncated version, but the end of the first page is
not a good place to truncate the letter.

This commit just extracts the code for showing multiple pages from the
template view, refactors it for reuse, and includes it in the send
views.

app/main/views/send.py

@@ -37,7 +37,7 @@ from app.utils import (
     get_help_argument,
     get_template
 )
-from app.template_previews import TemplatePreview
+from app.template_previews import TemplatePreview, get_page_count_for_letter
 
 
 def get_page_headings(template_type):
@@ -83,15 +83,19 @@ def get_example_letter_address(key):
 @user_has_permissions('send_texts', 'send_emails', 'send_letters')
 def send_messages(service_id, template_id):
 
+    template = service_api_client.get_service_template(service_id, template_id)['data']
+
     template = get_template(
-        service_api_client.get_service_template(service_id, template_id)['data'],
+        template,
         current_service,
         show_recipient=True,
+        expand_emails=True,
         letter_preview_url=url_for(
             '.view_letter_template_preview',
             service_id=service_id,
             template_id=template_id,
             filetype='png',
+            page_count=get_page_count_for_letter(template),
         ),
     )
 
@@ -150,15 +154,19 @@ def send_test(service_id, template_id):
 
     file_name = current_app.config['TEST_MESSAGE_FILENAME']
 
+    template = service_api_client.get_service_template(service_id, template_id)['data']
+
     template = get_template(
-        service_api_client.get_service_template(service_id, template_id)['data'],
+        template,
         current_service,
         show_recipient=True,
+        expand_emails=True,
         letter_preview_url=url_for(
             '.view_letter_template_preview',
             service_id=service_id,
             template_id=template_id,
             filetype='png',
+            page_count=get_page_count_for_letter(template),
         ),
     )
 

app/main/views/templates.py

@@ -19,7 +19,7 @@ from notifications_python_client.errors import HTTPError
 
 from app.main import main
 from app.utils import user_has_permissions, get_template
-from app.template_previews import TemplatePreview
+from app.template_previews import TemplatePreview, get_page_count_for_letter
 from app.main.forms import (
     ChooseTemplateType,
     SMSTemplateForm,
@@ -74,10 +74,6 @@ def choose_template(service_id):
 )
 def view_template(service_id, template_id):
     template = service_api_client.get_service_template(service_id, template_id)['data']
-    page_count = None
-    if template['template_type'] == 'letter':
-        page_count, _, _ = TemplatePreview.from_database_object(template, filetype='json')
-        page_count = json.loads(page_count.decode('utf-8'))['count']
     return render_template(
         'views/templates/template.html',
         template=get_template(
@@ -91,7 +87,7 @@ def view_template(service_id, template_id):
                 filetype='png',
             ),
             show_recipient=True,
-            page_count=page_count,
+            page_count=get_page_count_for_letter(template),
         ),
     )
 

app/template_previews.py

@@ -1,4 +1,4 @@
-from flask import current_app
+from flask import current_app, json
 import requests
 
 from app import current_service
@@ -32,3 +32,14 @@ class TemplatePreview:
             template.values,
             page=page,
         )
+
+
+def get_page_count_for_letter(template, values=None):
+
+    if template['template_type'] != 'letter':
+        return None
+
+    page_count, _, _ = TemplatePreview.from_database_object(template, values, filetype='json')
+    page_count = json.loads(page_count.decode('utf-8'))['count']
+
+    return page_count

tests/app/test_template_previews.py

@@ -4,7 +4,7 @@ from functools import partial
 from unittest.mock import Mock
 from notifications_utils.template import LetterPreviewTemplate
 
-from app.template_previews import TemplatePreview
+from app.template_previews import TemplatePreview, get_page_count_for_letter
 
 
 @pytest.mark.parametrize('partial_call, expected_page_argument', [
@@ -65,3 +65,32 @@ def test_from_database_object_makes_request(
     headers = {'Authorization': 'Token my-secret-key'}
 
     request_mock.assert_called_once_with(expected_url, json=data, headers=headers)
+
+
+@pytest.mark.parametrize('template_type', [
+    'email', 'sms'
+])
+def test_page_count_returns_none_for_non_letter_templates(template_type):
+    assert get_page_count_for_letter({'template_type': template_type}) is None
+
+
+@pytest.mark.parametrize('partial_call, expected_template_preview_args', [
+    (
+        partial(get_page_count_for_letter),
+        ({'template_type': 'letter'}, None)
+    ),
+    (
+        partial(get_page_count_for_letter, values={'foo': 'bar'}),
+        ({'template_type': 'letter'}, {'foo': 'bar'})
+    ),
+])
+def test_page_count_unpacks_from_json_response(
+    mocker,
+    partial_call,
+    expected_template_preview_args,
+):
+    mock_template_preview = mocker.patch('app.template_previews.TemplatePreview.from_database_object')
+    mock_template_preview.return_value = (b'{"count": 99}', 200, {})
+
+    assert partial_call({'template_type': 'letter'}) == 99
+    mock_template_preview.assert_called_once_with(*expected_template_preview_args, filetype='json')