code: def test_load_vars_from_file(tmp_dir, dvc):
      (tmp_dir / DEFAULT_PARAMS_FILE).dump(DATA)
  
      datasets = {"datasets": ["foo", "bar"]}
      (tmp_dir / "params.json").dump(datasets)
      d = {"vars": [DEFAULT_PARAMS_FILE, "params.json"]}
      resolver = DataResolver(dvc, tmp_dir.fs_path, d)
  
      expected = deepcopy(DATA)
      expected.update(datasets)
      assert resolver.context == expected
  
imports: from copy import deepcopy
  import pytest
  from dvc.parsing import DEFAULT_PARAMS_FILE, DataResolver, ResolveError
  from dvc.parsing.context import Context
  from dvc.utils.serialize import dumps_yaml
  from .None import CONTEXT_DATA, RESOLVED_DVC_YAML_DATA, TEMPLATED_DVC_YAML_DATA
label_desc: Use image node_id 7 for calling a global function with example usage: test_load_vars_from_file(tmp_dir, dvc) without return types