Add unit test and note in config form

Author: amenk

app/code/Magento/Theme/Block/Html/Footer.php

@@ -133,12 +133,12 @@ protected function getCacheLifetime()
     {
         return parent::getCacheLifetime() ?: 3600;
     }
-    
+
     /**
      * Replace YYYY by the current year
      */
     private function replaceCurrentYear(string $text): string
     {
-        return str_replace('YYYY', (new \DateTime())->format('Y'), $text)   
+        return str_replace('{YYYY}', (new \DateTime())->format('Y'), $text);
     }
 }

app/code/Magento/Theme/Test/Unit/Block/Html/FooterTest.php

@@ -8,9 +8,14 @@
 namespace Magento\Theme\Test\Unit\Block\Html;
 
 use Magento\Cms\Model\Block;
+use Magento\Framework\App\Config;
+use Magento\Framework\Escaper;
 use Magento\Framework\TestFramework\Unit\Helper\ObjectManager;
+use Magento\Framework\View\Element\Template\Context;
+use Magento\Store\Model\ScopeInterface;
 use Magento\Store\Model\Store;
 use Magento\Theme\Block\Html\Footer;
+use Magento\Theme\Block\Html\Header;
 use PHPUnit\Framework\TestCase;
 
 class FooterTest extends TestCase
@@ -23,14 +28,41 @@ class FooterTest extends TestCase
     protected function setUp(): void
     {
         $objectManager = new ObjectManager($this);
-        $this->block = $objectManager->getObject(Footer::class);
+
+        $context = $this->getMockBuilder(Context::class)
+            ->setMethods(['getScopeConfig'])
+            ->disableOriginalConstructor()
+            ->getMock();
+        $this->scopeConfig = $this->getMockBuilder(Config::class)
+            ->setMethods(['getValue'])
+            ->disableOriginalConstructor()
+            ->getMock();
+        $context->expects($this->once())->method('getScopeConfig')->willReturn($this->scopeConfig);
+
+        $this->block = $objectManager->getObject(
+            Footer::class,
+            [
+                'context' => $context,
+            ]
+        );
     }
 
     protected function tearDown(): void
     {
         $this->block = null;
     }
 
+    public function testGetCopyright()
+    {
+        $this->scopeConfig->expects($this->once())->method('getValue')
+            ->with('design/footer/copyright', ScopeInterface::SCOPE_STORE)
+            ->willReturn('Copyright 2013-{YYYY}');
+
+        $this->assertEquals(
+            'Copyright 2013-' . date('Y'),
+            $this->block->getCopyright()
+        );
+    }
     public function testGetIdentities()
     {
         $this->assertEquals(

app/code/Magento/Theme/i18n/en_US.csv

@@ -172,6 +172,7 @@ Header,Header
 Footer,Footer
 "This will be displayed just before the body closing tag.","This will be displayed just before the body closing tag."
 "Miscellaneous HTML","Miscellaneous HTML"
+"Use {YYYY} to insert the current year (updates on cache refresh).","Use {YYYY} to insert the current year (updates on cache refresh)."
 Copyright,Copyright
 "Default Robots","Default Robots"
 "Edit custom instruction of robots.txt File","Edit custom instruction of robots.txt File"

app/code/Magento/Theme/view/adminhtml/ui_component/design_config_form.xml

@@ -242,6 +242,7 @@
                     <validation>
                         <rule name="validate-no-html-tags" xsi:type="boolean">true</rule>
                     </validation>
+                    <notice translate="true">Use {YYYY} to insert the current year (updates on cache refresh).</notice>
                     <dataType>text</dataType>
                     <label translate="true">Copyright</label>
                     <dataScope>footer_copyright</dataScope>