Add update letter branding method to letter branding client

app/notify_client/letter_branding_client.py

@@ -20,5 +20,16 @@ class LetterBrandingClient(NotifyAdminAPIClient):
         }
         return self.post(url="/letter-branding", data=data)
 
+    @cache.delete('letter_branding')
+    @cache.delete('letter_branding-{branding_id}')
+    def update_letter_branding(self, branding_id, filename, name, domain):
+        data = {
+            "filename": filename,
+            "name": name,
+            "domain": domain,
+
+        }
+        return self.post(url="/letter-branding/{}".format(branding_id), data=data)
+
 
 letter_branding_client = LetterBrandingClient()

tests/app/notify_client/test_letter_branding_client.py

@@ -1,3 +1,5 @@
+from unittest.mock import call
+
 from app.notify_client.letter_branding_client import LetterBrandingClient
 
 
@@ -51,3 +53,21 @@ def test_create_letter_branding(mocker):
     )
 
     mock_redis_delete.assert_called_once_with('letter_branding')
+
+
+def test_update_letter_branding(mocker, fake_uuid):
+    branding = {'filename': 'uuid-test', 'name': 'my letters', 'domain': 'example.com'}
+
+    mock_post = mocker.patch('app.notify_client.letter_branding_client.LetterBrandingClient.post')
+    mock_redis_delete = mocker.patch('app.notify_client.RedisClient.delete')
+    LetterBrandingClient().update_letter_branding(
+        branding_id=fake_uuid, filename=branding['filename'], name=branding['name'], domain=branding['domain'])
+
+    mock_post.assert_called_once_with(
+        url='/letter-branding/{}'.format(fake_uuid),
+        data=branding
+    )
+    assert mock_redis_delete.call_args_list == [
+        call('letter_branding'),
+        call('letter_branding-{}'.format(fake_uuid)),
+    ]