add stats boxes to platform admin page

moved a couple of stats summary functions from dashboard to a shared statistics_utils file

tests/app/main/views/test_platform_admin.py

@@ -1,7 +1,12 @@
+from datetime import date
+
 from flask import url_for
+from freezegun import freeze_time
 
 from tests.conftest import mock_get_user
 
+from app.main.views.platform_admin import get_global_stats
+
 
 def test_should_redirect_if_not_logged_in(app_):
     with app_.test_request_context():
@@ -22,7 +27,7 @@ def test_should_403_if_not_platform_admin(app_, active_user_with_permissions, mo
             assert response.status_code == 403
 
 
-def test_should_render_platform_admin_page(app_, platform_admin_user, mocker):
+def test_should_render_platform_admin_page(app_, platform_admin_user, mocker, mock_get_all_service_statistics):
     with app_.test_request_context():
         with app_.test_client() as client:
             mock_get_user(mocker, user=platform_admin_user)
@@ -34,3 +39,21 @@ def test_should_render_platform_admin_page(app_, platform_admin_user, mocker):
             assert 'Platform admin' in resp_data
             assert 'List all services' in resp_data
             assert 'View providers' in resp_data
+
+
+def test_get_global_stats_should_summarise_all_stats(mock_get_all_service_statistics):
+    resp = get_global_stats()
+
+    assert 'emails_delivered' in resp
+    assert 'emails_failed' in resp
+    assert 'emails_failure_rate' in resp
+    assert 'sms_delivered' in resp
+    assert 'sms_failed' in resp
+    assert 'sms_failure_rate' in resp
+
+
+@freeze_time('2000-06-30T23:30:00', tz_offset=0)
+def test_get_global_stats_should_query_for_today_forced_to_GMT(mock_get_all_service_statistics):
+    get_global_stats()
+
+    mock_get_all_service_statistics.assert_called_once_with(date(2000, 7, 1))