diff --git a/plugins/bc-installer/src/Service/InstallationsService.php b/plugins/bc-installer/src/Service/InstallationsService.php
index 3ba40659c8..98813e8f28 100644
--- a/plugins/bc-installer/src/Service/InstallationsService.php
+++ b/plugins/bc-installer/src/Service/InstallationsService.php
@@ -586,6 +586,7 @@ public function getAllDefaultDataPatterns(): array
      * @param array $email
      * @checked
      * @noTodo
+     * @unitTest
      */
     public function sendCompleteMail(array $postData)
     {
diff --git a/plugins/bc-installer/tests/TestCase/Service/InstallationsServiceTest.php b/plugins/bc-installer/tests/TestCase/Service/InstallationsServiceTest.php
index 1809750cc1..5df63389af 100644
--- a/plugins/bc-installer/tests/TestCase/Service/InstallationsServiceTest.php
+++ b/plugins/bc-installer/tests/TestCase/Service/InstallationsServiceTest.php
@@ -14,6 +14,7 @@
 use BaserCore\Service\PermissionGroupsServiceInterface;
 use BaserCore\Test\Factory\ContentFactory;
 use BaserCore\Test\Factory\ContentFolderFactory;
+use BaserCore\Test\Factory\SiteConfigFactory;
 use BaserCore\Test\Factory\SiteFactory;
 use BaserCore\Test\Scenario\InitAppScenario;
 use BaserCore\TestSuite\BcTestCase;
@@ -198,6 +199,23 @@ public function testTestConnectDb()
         $this->Installations->testConnectDb($config);
     }
 
+    /**
+     * test sendCompleteMail
+     */
+    public function testSendCompleteMail()
+    {
+        //データを生成
+        SiteConfigFactory::make(['name' => 'email', 'value' => 'basertest@example.com'])->persist();
+
+        //正常テスト
+        $this->Installations->sendCompleteMail(['admin_email' => 'abc@example.example']);
+
+        //エラーを発生
+        $this->expectException(\InvalidArgumentException::class);
+        $this->expectExceptionMessage('The email set for `to` is empty.');
+        $this->Installations->sendCompleteMail(['admin_email' => '']);
+    }
+
     /**
      * test setAdminEmail
      */