diff --git a/SilMock/Google/Service/Directory.php b/SilMock/Google/Service/Directory.php
index 3955ffe..90b7bd5 100644
--- a/SilMock/Google/Service/Directory.php
+++ b/SilMock/Google/Service/Directory.php
@@ -5,6 +5,7 @@
 use Google\Client;
 use SilMock\Google\Http\Batch;
 use SilMock\Google\Service\Directory\Asps;
+use SilMock\Google\Service\Directory\Resource\Domains;
 use SilMock\Google\Service\Directory\Resource\Groups;
 use SilMock\Google\Service\Directory\Resource\GroupsAliases;
 use SilMock\Google\Service\Directory\Resource\Members;
@@ -18,6 +19,7 @@
 class Directory
 {
     public $asps;
+    public Domains $domains;
     public Members $members;
     public Groups $groups;
     public GroupsAliases $groups_aliases;
@@ -38,6 +40,7 @@ class Directory
     public function __construct($client, ?string $dbFile = null)
     {
         $this->asps = new Asps($dbFile);
+        $this->domains = new Domains($dbFile);
         $this->members = new Members($dbFile);
         $this->groups = new Groups($dbFile);
         $this->groups_aliases = new GroupsAliases($dbFile);
diff --git a/SilMock/Google/Service/Directory/Resource/Domains.php b/SilMock/Google/Service/Directory/Resource/Domains.php
new file mode 100644
index 0000000..2ad2a95
--- /dev/null
+++ b/SilMock/Google/Service/Directory/Resource/Domains.php
@@ -0,0 +1,32 @@
+<?php
+
+namespace SilMock\Google\Service\Directory\Resource;
+
+use Google\Service\Directory\Domains as GoogleDirectory_Domains;
+use Google\Service\Directory\Domains2 as GoogleDirectory_Domains2;
+use SilMock\Google\Service\DbClass;
+
+class Domains extends DbClass
+{
+    // default to the same as Group and Members
+    public function __construct(?string $dbFile = DATAFILE5)
+    {
+        parent::__construct($dbFile, 'directory', 'domains');
+    }
+
+    public function listDomains(string $customer, array $options = []): GoogleDirectory_Domains2
+    {
+        // no need to store anything at this time.
+        $domainNamesString = getenv('DOMAIN_NAMES');
+        $domainNames = explode(',', $domainNamesString);
+        $domains = [];
+        foreach ($domainNames as $domainName) {
+            $domain = new GoogleDirectory_Domains();
+            $domain->setDomainName($domainName);
+            $domains[] = $domain;
+        }
+        $domains2 = new GoogleDirectory_Domains2();
+        $domains2->setDomains($domains);
+        return $domains2;
+    }
+}
diff --git a/SilMock/tests/Google/Service/Directory/Resource/DomainsTest.php b/SilMock/tests/Google/Service/Directory/Resource/DomainsTest.php
new file mode 100644
index 0000000..712b210
--- /dev/null
+++ b/SilMock/tests/Google/Service/Directory/Resource/DomainsTest.php
@@ -0,0 +1,28 @@
+<?php
+
+namespace Service\Directory\Resource;
+
+use PHPUnit\Framework\TestCase;
+use SilMock\Google\Service\Directory\Resource\Domains;
+
+class DomainsTest extends TestCase
+{
+    public function testListDomains()
+    {
+        $domainsApi = new Domains();
+        $domainNameListObject = $domainsApi->listDomains('any_customer');
+        $arrayOfDomainsObjects = $domainNameListObject->getDomains();
+        $domainNameList = [];
+        foreach ($arrayOfDomainsObjects as $domainObject) {
+            $domainNameList[$domainObject->getDomainName()] = $domainObject->getDomainName();
+        }
+        // This should match the values in docker-compose.yml when testing locally
+        // This should match the values in run-tests.sh when testing is triggered by GitHub actions
+        // This is the keyed array version of the list.
+        $expected = [
+            'groups.example.org' => 'groups.example.org',
+            'example.org' => 'example.org',
+        ];
+        self::assertEquals($expected, $domainNameList, 'Domain name list does not match expected values');
+    }
+}
diff --git a/composer.json b/composer.json
index e5c2b3d..af937bb 100644
--- a/composer.json
+++ b/composer.json
@@ -1,6 +1,6 @@
 {
     "name": "silinternational/google-api-php-client-mock",
-    "version": "2.13.2",
+    "version": "2.14.0",
     "description": "Attempting to create an intelligent mock of the Google API PHP Client for unit and functional testing.",
     "type": "library",
     "keywords": [
diff --git a/composer.lock b/composer.lock
index 48042bb..2b1d99f 100644
--- a/composer.lock
+++ b/composer.lock
@@ -4,7 +4,7 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "content-hash": "6a6776cd80056ba0e3e3e1e8ae7f6e7d",
+    "content-hash": "1e021a94f9075dbd119cd1e3e5d7889a",
     "packages": [
         {
             "name": "firebase/php-jwt",
diff --git a/docker-compose.yml b/docker-compose.yml
index d993523..2b4617b 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -5,6 +5,9 @@ services:
         volumes:
             - ./:/data
         working_dir: /data
+        environment:
+            # This should match the value in run-tests.sh
+            - DOMAIN_NAMES=groups.example.org,example.org
         command: ["true"]
 
 networks:
diff --git a/run-tests.sh b/run-tests.sh
index b822352..62f7ac9 100755
--- a/run-tests.sh
+++ b/run-tests.sh
@@ -2,4 +2,5 @@
 
 
 cd /data/SilMock/tests
-./phpunit
+# This should match the value in docker-compose.yml
+DOMAIN_NAMES=groups.example.org,example.org ./phpunit