Improve functions with null domains

Author: nyamsprod

src/functions.php

@@ -33,8 +33,12 @@ function append($host, $subject): Domain
         return $subject;
     }
 
-    static $pattern = '/[^\x20-\x7f]/';
     $dContent = $subject->getContent();
+    if (null === $dContent) {
+        return $host instanceof DomainInterface ? new Domain($host) : $host;
+    }
+
+    static $pattern = '/[^\x20-\x7f]/';
     $host = preg_match($pattern, $dContent) ? $host->toUnicode() : $host->toAscii();
     $domain = new Domain($dContent.'.'.$host->getContent());
 
@@ -64,14 +68,18 @@ function prepend($host, $subject): Domain
     }
 
     if (!$host instanceof DomainInterface) {
-        $host = new PublicSuffix($host);
+        $host = new Domain($host);
     }
 
     if (null === $host->getContent()) {
         return $subject;
     }
 
     $dContent = $subject->getContent();
+    if (null === $dContent) {
+        return $host instanceof DomainInterface ? new Domain($host) : $host;
+    }
+
     static $pattern = '/[^\x20-\x7f]/';
     $host = preg_match($pattern, $dContent) ? $host->toUnicode() : $host->toAscii();
 

tests/FunctionsTest.php

@@ -52,14 +52,22 @@ public function prependProvider()
                 'isIcann' => false,
                 'isPrivate' => false,
             ],
-            'prepend a null domain' => [
+            'prepend with a null domain' => [
                 'domain' => 'example.com',
                 'host' => null,
                 'expected' => 'example.com',
                 'isKnown' => false,
                 'isIcann' => false,
                 'isPrivate' => false,
             ],
+            'prepend a null domain' => [
+                'domain' => null,
+                'host' => 'example.com',
+                'expected' => 'example.com',
+                'isKnown' => false,
+                'isIcann' => false,
+                'isPrivate' => false,
+            ],
             'prepend does not change PSL info (1)' => [
                 'domain' => new Domain('example.com', new PublicSuffix('com', Rules::ICANN_DOMAINS)),
                 'host' => new Domain(),
@@ -178,7 +186,15 @@ public function appendProvider()
                 'isIcann' => false,
                 'isPrivate' => false,
             ],
-            'adding a null public suffix returns the domain only' => [
+            'append a null domain' => [
+                'domain' => null,
+                'host' => 'example.com',
+                'expected' => 'example.com',
+                'isKnown' => false,
+                'isIcann' => false,
+                'isPrivate' => false,
+            ],
+            'append with a null domain' => [
                 'domain' => 'example.com',
                 'host' => null,
                 'expected' => 'example.com',