Add test for Fiber::getCoroutine() method

Author: EdmondDantes

tests/fiber/019-fiber_getCoroutine.phpt

@@ -0,0 +1,48 @@
+--TEST--
+Fiber::getCoroutine() method
+--FILE--
+<?php
+
+use function Async\spawn;
+use function Async\await;
+
+// Test with coroutine
+$c = spawn(function() {
+    $f = new Fiber(function() {
+        Fiber::suspend();
+    });
+
+    $f->start();
+
+    $coro = $f->getCoroutine();
+    echo "Has coroutine: " . ($coro !== null ? "yes" : "no") . "\n";
+    echo "Coroutine ID: " . $coro->getId() . "\n";
+    echo "Is started: " . ($coro->isStarted() ? "yes" : "no") . "\n";
+    echo "Is suspended: " . ($coro->isSuspended() ? "yes" : "no") . "\n";
+
+    $f->resume();
+});
+
+await($c);
+
+// Test without coroutine (regular fiber)
+$f = new Fiber(function() {
+    Fiber::suspend();
+});
+
+$f->start();
+
+$coro = $f->getCoroutine();
+echo "Regular fiber coroutine: " . ($coro === null ? "null" : "not-null") . "\n";
+
+$f->resume();
+
+echo "OK\n";
+?>
+--EXPECT--
+Has coroutine: yes
+Coroutine ID: 2
+Is started: yes
+Is suspended: yes
+Regular fiber coroutine: null
+OK