[k2] add tests for get_running_fork_id

tests/python/tests/coroutine/php/data/component-config.yaml

@@ -0,0 +1,7 @@
+entry: script
+components:
+  script:
+    image: KPHP
+    scope: Request
+    args: {}
+    links: {}

tests/python/tests/coroutine/php/index.php

@@ -0,0 +1,54 @@
+<?php
+
+function test_get_running_fork_id() {
+  $f = function() {
+    // 1. Non-"main" fork. Before std function which is coroutine
+    $before = (int)get_running_fork_id();
+
+    sched_yield_sleep(0.01);
+
+    $nested_f = function () {
+      // 2. Yet another non-"main" fork. Before std function which is coroutine
+      $before = (int)get_running_fork_id();
+      sched_yield_sleep(0.01);
+      assert_fork_id($before);
+      return null;
+    };
+
+    assert_fork_id($before);
+    $fut = fork($nested_f());
+    assert_fork_id($before);
+    wait($fut);
+    assert_fork_id($before);
+    return null;
+  };
+  $fut = fork($f());
+
+  // 3. "main" fork. Before std function which is coroutine
+  $before = (int)get_running_fork_id();
+  sched_yield_sleep(0.01);
+  assert_fork_id($before);
+  wait($fut);
+  assert_fork_id($before);
+}
+
+
+function assert_fork_id(int $expected_fork_id) {
+  $current_fork_id = (int)get_running_fork_id();
+  if ($current_fork_id != $expected_fork_id) {
+    critical_error("unexpected fork id, expected: " . $expected_fork_id . "  got: " . $current_fork_id);
+  }
+}
+
+function main() {
+  switch ($_SERVER["PHP_SELF"]) {
+    case "/test_get_running_fork_id": {
+        test_get_running_fork_id();
+        return;
+      }
+  }
+
+  critical_error("unknown test");
+}
+
+main();

tests/python/tests/coroutine/test_get_running_fork_id.py

@@ -0,0 +1,17 @@
+import socket
+import pytest
+
+from python.lib.testcase import WebServerAutoTestCase
+from python.lib.http_client import RawResponse
+
+class TestErrors(WebServerAutoTestCase):
+    @classmethod
+    def extra_class_setup(cls):
+        if not cls.should_use_k2():
+            cls.web_server.update_options({
+                "--workers-num": 1
+            })
+
+    def test_get_running_fork_id(self):
+        response = self.web_server.http_request(uri="/test_get_running_fork_id", method='GET')
+        self.assertEqual(200, response.status_code)