Add success message on success

Author: fredden

app/code/Magento/SampleData/Console/Command/SampleDataDeployCommand.php

@@ -140,6 +140,8 @@ protected function execute(InputInterface $input, OutputInterface $output)
                 return Cli::RETURN_FAILURE;
             }
 
+            $output->writeln('<info>' . 'Sample data modules have been added via composer. Please run bin/magento setup:upgrade' . '</info>');
+
             return Cli::RETURN_SUCCESS;
         } else {
             $output->writeln('<info>' . 'There is no sample data for current set of modules.' . '</info>');

app/code/Magento/SampleData/Test/Unit/Console/Command/SampleDataDeployCommandTest.php

@@ -163,7 +163,8 @@ public function processDataProvider(): array
                 'composerJsonContent' => [
                     'require' => ["magento/product-community-edition" => "0.0.1"],
                 ],
-                'expectedMsg' => '',
+                'expectedMsg' => 'Sample data modules have been added via composer. Please run bin/magento setup:upgrade'
+                    . PHP_EOL,
                 'authExist' => true,
             ],
         ];