diff --git a/test/POP3/PopBeforeSmtpTest.php b/test/POP3/PopBeforeSmtpTest.php
index e34b6000..49c313af 100644
--- a/test/POP3/PopBeforeSmtpTest.php
+++ b/test/POP3/PopBeforeSmtpTest.php
@@ -47,6 +47,16 @@ final class PopBeforeSmtpTest extends TestCase
         }
     }
 
+    /**
+     * Run before each test is started.
+     */
+    protected function set_up()
+    {
+        if (DIRECTORY_SEPARATOR === '\\') {
+            $this->markTestSkipped('This test needs a non-Windows OS to run');
+        }
+    }
+
     /**
      * Run after each test is completed.
      */