Fix test cases (#6)

python/sglang/api.py

@@ -17,13 +17,19 @@ from sglang.lang.ir import (
     SglRoleEnd,
     SglSelect,
 )
-from sglang.srt.server import Runtime
 
 
 def function(func: Callable):
     return SglFunction(func)
 
 
+def Runtime(*args, **kwargs):
+    # Avoid importing unnecessary dependency
+    from sglang.srt.server import Runtime
+
+    return Runtime(*args, **kwargs)
+
+
 def set_default_backend(backend: BaseBackend):
     global_config.default_backend = backend