* Fix tests php 5.5

Author: Ivan Lutokhin

EmailValidator/Validation/Error/IllegalMailbox.php

@@ -33,4 +33,17 @@ public function getResponseCode()
     {
         return $this->responseCode;
     }
+
+    /**
+     * @return string
+     */
+    public function __toString()
+    {
+        return sprintf(
+            "%s SMTP response code: %s. Internal code: %s.",
+            $this->message,
+            $this->responseCode,
+            $this->code
+        );
+    }
 }

Tests/EmailValidator/Validation/MailboxCheckValidationTest.php

@@ -13,7 +13,12 @@ class MailboxCheckValidationTest extends TestCase
 {
     public function testValidMailbox()
     {
-        $socketHelperMock = $this->createMock(SmtpSocketHelper::class);
+        $socketHelperMock = $this->getMockBuilder(SmtpSocketHelper::class)
+            ->disableOriginalConstructor()
+            ->disableOriginalClone()
+            ->disableArgumentCloning()
+            ->disallowMockingUnknownTypes()
+            ->getMock();
 
         $socketHelperMock
             ->expects($this->any())
@@ -42,7 +47,12 @@ public function testDNSWarnings()
 
     public function testIllegalMailboxError()
     {
-        $socketHelperMock = $this->createMock(SmtpSocketHelper::class);
+        $socketHelperMock = $this->getMockBuilder(SmtpSocketHelper::class)
+            ->disableOriginalConstructor()
+            ->disableOriginalClone()
+            ->disableArgumentCloning()
+            ->disallowMockingUnknownTypes()
+            ->getMock();
 
         $socketHelperMock
             ->expects($this->any())