code: def test_scm_track_file(scm_context):
      scm_context.track_file("foo")
      assert scm_context.files_to_track == {"foo"}
      scm_context.track_file("bar")
      assert scm_context.files_to_track == {"foo", "bar"}
  
file_path: dvc/tests/unit/repo/test_scm_context.py
imports: import re
  import pytest
  from dvc.repo.scm_context import SCMContext
  from dvc.scm import Git, NoSCM
label_desc: Use image node_id 3 for calling a global function with example usage: test_scm_track_file(scm_context) without return types