clients: cbc_proxy invokes hardcoded function

right now we are doing an end-to-end journey with a CBC from Notify (the
CBE) and we would like to approve a broadcast in notify and have it
appear on our test handset

in order to do this, we:
* hook up the lambda that we made in the correct VPC to cbc_proxy client
* test that it is called correctly

Signed-off-by: Toby Lorne <toby.lornewelch-richards@digital.cabinet-office.gov.uk>
Co-authored-by: Pea <pea.tyczynska@digital.cabinet-office.gov.uk>
Co-authored-by: Katie <katie.smith@digital.cabinet-office.gov.uk>

tests/app/clients/test_cbc_proxy.py

@@ -1,3 +1,5 @@
+import json
+
 import pytest
 
 from app.clients.cbc_proxy import CBCProxyClient
@@ -25,3 +27,35 @@ def test_cbc_proxy_ld_client_has_correct_keys(cbc_proxy):
 
     assert key == 'cbc-proxy-aws-access-key-id'
     assert secret == 'cbc-proxy-aws-secret-access-key'
+
+
+def test_cbc_proxy_create_and_send_invokes_function(mocker, cbc_proxy):
+    identifier = 'my-identifier'
+    headline = 'my-headline'
+    description = 'my-description'
+
+    ld_client_mock = mocker.patch.object(
+        cbc_proxy,
+        '_ld_client',
+        create=True,
+    )
+
+    cbc_proxy.create_and_send_broadcast(
+        identifier=identifier,
+        headline=headline,
+        description=description,
+    )
+
+    ld_client_mock.invoke.assert_called_once_with(
+        FunctionName='bt-ee-1-proxy',
+        InvocationType='RequestResponse',
+        Payload=mocker.ANY,
+    )
+
+    kwargs = ld_client_mock.invoke.mock_calls[0][-1]
+    payload_bytes = kwargs['Payload']
+    payload = json.loads(payload_bytes)
+
+    assert payload['identifier'] == identifier
+    assert payload['headline'] == headline
+    assert payload['description'] == description