old_contents: import pytest
  
  from ..core import diff_dicts
  
  
  @pytest.mark.parametrize('value_dicts, diff_keys', [
      ([dict(a=1)] * 2, []),
      ([dict(a=1), dict(a=2)], ['a']),
      ([dict(a=1), dict(b=1)], ['a', 'b']),
      ([dict(a=[1]), dict(a=[1])], []),
      ([dict(a=[1]), dict(a=[2])], ['a']),
  ])
  def test_diff_flat_keys(value_dicts, diff_keys):
      dd = diff_dicts(value_dicts)
      assert dd.keys == sorted((k,) for k in diff_keys)
  
  
  @pytest.mark.parametrize('value_dicts, diff_keys, rtol, atol', [
      ([dict(a=1.0)] * 2, [], 0, 0),
      ([dict(a=1.0), dict(a=0.999)], ['a'], 0, 0),
      ([dict(a=1.0), dict(a=0.999)], [], 1e-2, 0),
      ([dict(a=1.0), dict(a=0.999)], [], 0, 1e-2),
  ])
  def test_float_diff_with_tol(value_dicts, diff_keys, rtol, atol):
      dd = diff_dicts(value_dicts, rtol=rtol, atol=atol)
      assert dd.keys == sorted((k,) for k in diff_keys)
  
new_contents: import pytest
  
  from ..core import DictsDiff, diff_dicts
  
  
  @pytest.mark.parametrize('value_dicts, diff_keys', [
      ([dict(a=1)] * 2, []),
      ([dict(a=1), dict(a=2)], ['a']),
      ([dict(a=1), dict(b=1)], ['a', 'b']),
      ([dict(a=[1]), dict(a=[1])], []),
      ([dict(a=[1]), dict(a=[2])], ['a']),
  ])
  def test_diff_flat_keys(value_dicts, diff_keys):
      dd = diff_dicts(value_dicts)
      assert dd.keys == sorted((k,) for k in diff_keys)
  
  
  @pytest.mark.parametrize('value_dicts, diff_keys, rtol, atol', [
      ([dict(a=1.0)] * 2, [], 0, 0),
      ([dict(a=1.0), dict(a=0.999)], ['a'], 0, 0),
      ([dict(a=1.0), dict(a=0.999)], [], 1e-2, 0),
      ([dict(a=1.0), dict(a=0.999)], [], 0, 1e-2),
  ])
  def test_float_diff_with_tol(value_dicts, diff_keys, rtol, atol):
      dd = diff_dicts(value_dicts, rtol=rtol, atol=atol)
      assert dd.keys == sorted((k,) for k in diff_keys)
  
  
  def test_info_keys_with_nonempty_info_dicts():
      dd = DictsDiff(
          [dict(a=dict(b=111, c=0)), dict(a=dict(b=222, c=1))],
          [dict(path='x'), dict(path='y')],
          info_keys=[('a', 'b')],
      )
      df = dd.pretty_diff()
      assert list(df.columns) == ['a.c']
      assert list(df.index.names) == ['a.b']
      assert list(df.index) == [111, 222]
  
  
  def test_info_keys_with_empty_info_dicts():
      dd = diff_dicts(
          [dict(a=dict(b=111, c=0)), dict(a=dict(b=222, c=1))],
          info_keys=[('a', 'b')],
      )
      df = dd.pretty_diff()
      assert list(df.columns) == ['a.c']
      assert list(df.index.names) == ['a.b']
      assert list(df.index) == [111, 222]
  
subject: Add test_info_keys_*