[11.x] improvement test for string title (#51015)

* test(SupportStrTest.php): improvement test for string title

* test(SupportStrTest.php): add test for special characters

* fix: code style

tests/Support/SupportStrTest.php

@@ -37,6 +37,17 @@ public function testStringTitle()
     {
         $this->assertSame('Jefferson Costella', Str::title('jefferson costella'));
         $this->assertSame('Jefferson Costella', Str::title('jefFErson coSTella'));
+
+        $this->assertSame('', Str::title(''));
+        $this->assertSame('123 Laravel', Str::title('123 laravel'));
+        $this->assertSame('❤Laravel', Str::title('❤laravel'));
+        $this->assertSame('Laravel ❤', Str::title('laravel ❤'));
+        $this->assertSame('Laravel123', Str::title('laravel123'));
+        $this->assertSame('Laravel123', Str::title('Laravel123'));
+
+        $longString = 'lorem ipsum '.str_repeat('dolor sit amet ', 1000);
+        $expectedResult = 'Lorem Ipsum Dolor Sit Amet '.str_repeat('Dolor Sit Amet ', 999);
+        $this->assertSame($expectedResult, Str::title($longString));
     }
 
     public function testStringHeadline()