Letter job can't be cancelled if already printed

Non-cancellable letter statuses mean that it's too late to cancel a job

tests/app/test_utils.py

@@ -13,6 +13,7 @@ from app.utils import (
     generate_next_dict,
     generate_notifications_csv,
     generate_previous_dict,
+    get_letter_printing_statement,
     get_logo_cdn_domain,
     printing_today_or_tomorrow,
 )
@@ -367,3 +368,39 @@ def test_printing_today_or_tomorrow_returns_today(utc_datetime):
 def test_printing_today_or_tomorrow_returns_tomorrow(datetime):
     with freeze_time(datetime):
         assert printing_today_or_tomorrow() == 'tomorrow'
+
+
+@pytest.mark.parametrize('created_at, current_datetime', [
+    ('2017-07-07T12:00:00+00:00', '2017-07-07 16:29:00'),  # created today, summer
+    ('2017-12-12T12:00:00+00:00', '2017-12-12 17:29:00'),  # created today, winter
+    ('2017-12-12T21:30:00+00:00', '2017-12-13 17:29:00'),  # created after 5:30 yesterday
+    ('2017-03-25T17:31:00+00:00', '2017-03-26 16:29:00'),  # over clock change period on 2017-03-26
+])
+def test_get_letter_printing_statement_when_letter_prints_today(created_at, current_datetime):
+    with freeze_time(current_datetime):
+        statement = get_letter_printing_statement('created', created_at)
+
+    assert statement == 'Printing starts today at 5:30pm'
+
+
+@pytest.mark.parametrize('created_at, current_datetime', [
+    ('2017-07-07T16:31:00+00:00', '2017-07-07 22:59:00'),  # created today, summer
+    ('2017-12-12T17:31:00+00:00', '2017-12-12 23:59:00'),  # created today, winter
+])
+def test_get_letter_printing_statement_when_letter_prints_tomorrow(created_at, current_datetime):
+    with freeze_time(current_datetime):
+        statement = get_letter_printing_statement('created', created_at)
+
+    assert statement == 'Printing starts tomorrow at 5:30pm'
+
+
+@pytest.mark.parametrize('created_at, print_day', [
+    ('2017-07-06T16:29:00+00:00', 'yesterday'),
+    ('2017-12-01T00:00:00+00:00', 'on 1 December'),
+    ('2017-03-26T12:00:00+00:00', 'on 26 March'),
+])
+@freeze_time('2017-07-07 12:00:00')
+def test_get_letter_printing_statement_for_letter_that_has_been_sent(created_at, print_day):
+    statement = get_letter_printing_statement('delivered', created_at)
+
+    assert statement == 'Printed {} at 5:30pm'.format(print_day)