Send domain invitations to particular email addresses, tests don't work

src/registrar/management/commands/send_domain_invitations.py

@@ -37,14 +37,28 @@ class Command(BaseCommand):
             help="Send emails ",
         )
 
+        parser.add_argument(
+            "emails",
+            nargs="*",
+            help="Email addresses to send invitations to"
+        )
+
     def handle(self, **options):
         """Process the objects in TransitionDomain."""
 
         logger.info("checking domains and preparing emails")
-        # Get all TransitionDomain objects
-        self.transition_domains = TransitionDomain.objects.filter(
-            email_sent=False,
-        ).order_by("username")
+
+        if options["emails"]:
+            # this option is a list of email addresses
+            self.transition_domains = TransitionDomain.objects.filter(
+                username__in=options["emails"],
+                email_sent=False,
+            ).order_by("username")
+        else:
+            # Get all TransitionDomain objects
+            self.transition_domains = TransitionDomain.objects.filter(
+                email_sent=False,
+            ).order_by("username")
         logger.info("Found %d transition domains", len(self.transition_domains))
 
         self.build_emails_to_send_array()

src/registrar/tests/test_transition_domain_migrations.py

@@ -1,3 +1,5 @@
+from io import StringIO
+
 from django.test import TestCase
 
 from registrar.models import (
@@ -11,6 +13,8 @@ from registrar.models import (
 
 from django.core.management import call_command
 
+from .common import less_console_noise
+
 
 class TestLogins(TestCase):
 
@@ -259,3 +263,20 @@ class TestLogins(TestCase):
             expected_missing_domain_informations,
             expected_missing_domain_invitations,
         )
+
+    def test_send_domain_invitations_email(self):
+        """Can send only a single domain invitation email."""
+        with less_console_noise():
+            self.run_load_domains()
+            self.run_transfer_domains()
+
+        # this is one of the email addresses in data/test_contacts.txt
+        output_stream = StringIO()
+        call_command("send_domain_invitations", 
+                     stdout=output_stream)
+
+        # Check that we had the right numbers in our output
+        output = output_stream.getvalue()
+        print("Output:", output)
+        self.assertIn("Found 1 transition domains", output)
+        self.assertTrue("would send email to testuser@gmail.com", output)