feat: added onlyOn* methods to run the test only on a specific OS

src/PendingCalls/TestCall.php

@@ -223,6 +223,30 @@ final class TestCall
         return $this->skipOn('Linux', 'This test is skipped on [Linux].');
     }
 
+    /**
+     * Runs the current test only if the given test is running on Windows.
+     */
+    public function onlyOnWindows(): self
+    {
+        return $this->skipOnLinux()->skipOnMac();
+    }
+
+    /**
+     * Runs the current test only if the given test is running on Mac.
+     */
+    public function onlyOnMac(): self
+    {
+        return $this->skipOnWindows()->skipOnLinux();
+    }
+
+    /**
+     * Run the current test only if the given test is running on Linux.
+     */
+    public function onlyOnLinux(): self
+    {
+        return $this->skipOnWindows()->skipOnMac();
+    }
+
     /**
      * Skips the current test if the given test is running on the given operating systems.
      */