Fix getObjectName()

When there is a getter without a prefix and a setter there is a difference in getObjectName
because there are two differents keys.
For example:
we had "myVar" and "MyVar" for the same property called "myVar".

Author: roukmoute

src/DtoTest.php

@@ -17,6 +17,7 @@
 use Roave\BetterReflection\Reflection\ReflectionClass;
 use Roave\BetterReflection\Reflection\ReflectionMethod;
 use RuntimeException;
+use function lcfirst;
 
 abstract class DtoTest extends TestCase
 {
@@ -146,6 +147,6 @@ private function getObjectName(bool $isGetterWithoutPrefix, string $methodName):
             return $methodName;
         }
 
-        return mb_substr($methodName, mb_substr($methodName, 0, 2) === 'is' ? 2 : 3);
+        return lcfirst(mb_substr($methodName, mb_substr($methodName, 0, 2) === 'is' ? 2 : 3));
     }
 }

tests/PHPUnit/Primitive.php

@@ -42,6 +42,9 @@ class Primitive
     /** @var self */
     private $primitiveImmutable;
 
+    /** @var string */
+    private $string2;
+
     public function isBool(): bool
     {
         return $this->bool;
@@ -121,4 +124,14 @@ public function primitiveImmutable(): self
     {
         return $this->primitiveImmutable;
     }
+
+    public function string2(): string
+    {
+        return $this->string2;
+    }
+
+    public function setString2(string $string): void
+    {
+        $this->string2 = $string;
+    }
 }