[CI] Batch CPU test workers (#37252)

test/registered/unit/test_fork_test_worker.py

@@ -54,14 +54,28 @@ class TestForkTestWorker(CustomTestCase):
                         assert "SGLANG_FORK_WORKER_TEST" not in os.environ
                         raise SystemExit(3)
                         """))
+                helper = Path(tmpdir) / "sibling_helper.py"
+                helper.write_text("VALUE = 42\n")
+                sibling_import = Path(tmpdir) / "sibling_import.py"
+                sibling_import.write_text(textwrap.dedent("""
+                        import os
+                        import sys
+
+                        from sibling_helper import VALUE
+
+                        assert sys.path[0] == os.path.dirname(__file__)
+                        assert VALUE == 42
+                        """))
 
                 results = []
-                for filename in (first, second):
+                for filename in (first, second, sibling_import):
                     process.stdin.write(json.dumps({"filename": str(filename)}) + "\n")
                     process.stdin.flush()
                     results.append(json.loads(result_stream.readline()))
 
-                self.assertEqual([result["returncode"] for result in results], [0, 3])
+                self.assertEqual(
+                    [result["returncode"] for result in results], [0, 3, 0]
+                )
                 self.assertTrue(all(result["elapsed"] >= 0 for result in results))
 
                 process.stdin.write(json.dumps({"command": "stop"}) + "\n")