Short circuit if already a team member

It would be confusing if people got invited twice, so let’s tell people
if someone’s already been invited.

app/main/views/manage_users.py

@@ -65,6 +65,11 @@ def invite_user(service_id, user_id=None):
 
     if user_id:
         user_to_invite = User.from_id(user_id)
+        if user_to_invite.belongs_to_service(current_service.id):
+            return render_template(
+                'views/user-already-invited.html',
+                user_to_invite=user_to_invite,
+            )
         form.email_address.data = user_to_invite.email_address
     else:
         user_to_invite = None

app/templates/views/user-already-invited.html

@@ -0,0 +1,19 @@
+{% extends "withnav_template.html" %}
+{% from "components/page-header.html" import page_header %}
+
+{% block service_page_title %}
+  This person is already a team member
+{% endblock %}
+
+{% block maincolumn_content %}
+
+  {{ page_header(
+    '{} is already a team member'.format(user_to_invite.name),
+    back_link=url_for('main.manage_users', service_id=current_service.id)
+  ) }}
+
+  <p class="govuk-body">
+    Someone’s already invited them. You do not need to do anything.
+  </p>
+
+{% endblock %}

tests/app/main/views/test_manage_users.py

@@ -807,10 +807,54 @@ def test_should_show_page_for_inviting_user(
 
 
 def test_should_show_page_for_inviting_user_with_email_prefilled(
+    mocker,
     client_request,
     mock_get_template_folders,
     fake_uuid,
+    active_user_with_permissions,
+    active_user_with_permission_to_other_service,
 ):
+    mocker.patch('app.models.user.user_api_client.get_user', side_effect=[
+        # First call is to get the current user
+        active_user_with_permissions,
+        # Second call gets the user to invite
+        active_user_with_permission_to_other_service,
+    ])
+
+    page = client_request.get(
+        'main.invite_user',
+        service_id=SERVICE_ONE_ID,
+        user_id=fake_uuid,
+        # We have the user’s name in the H1 but don’t want it duplicated
+        # in the page title
+        _test_page_title=False,
+    )
+    assert normalize_spaces(page.select_one('title').text).startswith(
+        'Invite a team member'
+    )
+    assert normalize_spaces(page.select_one('h1').text) == (
+        'Invite Service Two User'
+    )
+    assert normalize_spaces(page.select_one('main .govuk-body').text) == (
+        'service-two-user@test.gov.uk'
+    )
+    assert not page.select("input#email_address") or page.select("input[type=email]")
+
+
+def test_should_show_page_if_prefilled_user_is_already_a_team_member(
+    mocker,
+    client_request,
+    mock_get_template_folders,
+    fake_uuid,
+    active_user_with_permissions,
+    active_caseworking_user,
+):
+    mocker.patch('app.models.user.user_api_client.get_user', side_effect=[
+        # First call is to get the current user
+        active_user_with_permissions,
+        # Second call gets the user to invite
+        active_caseworking_user,
+    ])
     page = client_request.get(
         'main.invite_user',
         service_id=SERVICE_ONE_ID,
@@ -820,13 +864,16 @@ def test_should_show_page_for_inviting_user_with_email_prefilled(
         _test_page_title=False,
     )
 
+    assert normalize_spaces(page.select_one('title').text).startswith(
+        'This person is already a team member'
+    )
     assert normalize_spaces(page.select_one('h1').text) == (
-        'Invite Test User'
+        'Test User is already a team member'
     )
     assert normalize_spaces(page.select_one('main .govuk-body').text) == (
-        'test@user.gov.uk'
+        'Someone’s already invited them. You do not need to do anything.'
     )
-    assert not page.select("input#email_address") or page.select("input[type=email]")
+    assert not page.select("form")
 
 
 def test_should_show_folder_permission_form_if_service_has_folder_permissions_enabled(
@@ -903,7 +950,7 @@ def test_invite_user(
 def test_invite_user_when_email_address_is_prefilled(
     client_request,
     active_user_with_permissions,
-    active_caseworking_user,
+    active_user_with_permission_to_other_service,
     fake_uuid,
     mocker,
     sample_invite,
@@ -913,7 +960,7 @@ def test_invite_user_when_email_address_is_prefilled(
         # First call is to get the current user
         active_user_with_permissions,
         # Second call gets the user to invite
-        active_caseworking_user,
+        active_user_with_permission_to_other_service,
     ])
     mocker.patch('app.invite_api_client.create_invite', return_value=sample_invite)
     client_request.post(
@@ -931,7 +978,7 @@ def test_invite_user_when_email_address_is_prefilled(
     app.invite_api_client.create_invite.assert_called_once_with(
         active_user_with_permissions['id'],
         SERVICE_ONE_ID,
-        active_caseworking_user['email_address'],
+        active_user_with_permission_to_other_service['email_address'],
         {'send_messages'},
         'sms_auth',
         [],

tests/conftest.py

@@ -1315,6 +1315,21 @@ def active_user_with_permission_to_two_services(fake_uuid):
     }
 
 
+@pytest.fixture(scope='function')
+def active_user_with_permission_to_other_service(
+    active_user_with_permission_to_two_services
+):
+    active_user_with_permission_to_two_services['permissions'].pop(SERVICE_ONE_ID)
+    active_user_with_permission_to_two_services['services'].pop(0)
+    active_user_with_permission_to_two_services['name'] = (
+        'Service Two User'
+    )
+    active_user_with_permission_to_two_services['email_address'] = (
+        'service-two-user@test.gov.uk'
+    )
+    return active_user_with_permission_to_two_services
+
+
 @pytest.fixture(scope='function')
 def active_caseworking_user(fake_uuid):