code: def test_string_ordering():
      """Prefer ordering tasks by name first."""
      dsk = {("a", 1): (f,), ("a", 2): (f,), ("a", 3): (f,)}
      o = order(dsk)
      assert o == {("a", 1): 0, ("a", 2): 1, ("a", 3): 2}
  
imports: import pytest
  from flash.core.serve.dag.order import ndependencies, order
  from flash.core.serve.dag.task import get, get_deps
  from flash.core.serve.dag.utils_test import add, inc
  from flash.core.utilities.imports import _TOPIC_SERVE_AVAILABLE
label_desc: Use image node_id 19 for calling a global function with example usage: test_string_ordering() without return types