text: import pytest
  
  from nanotune.drivers.dac_interface import DACChannelInterface
  from nanotune.drivers.mock_dac import MockDAC, MockDACChannel
  
  
  def test_dacchannelinterface_methods():
      expected_methods = {
          "supports_hardware_ramp",
          "set_voltage",
          "get_voltage",
          "set_voltage_limit",
          "get_voltage_limit",
          "set_voltage_step",
          "get_voltage_step",
          "get_frequency",
          "set_frequency",
          "set_offset",
          "get_offset",
          "set_amplitude",
          "get_amplitude",
          "set_relay_state",
          "get_relay_state",
          "ramp_voltage",
          "set_ramp_rate",
          "get_ramp_rate",
          "get_waveform",
          "set_waveform",
      }
  
      f_set = DACChannelInterface.__abstractmethods__
      assert expected_methods == f_set
  
  
  def test_dacinterface_attributes_and_methods():
      dac = MockDAC("dummy_dac", MockDACChannel)
      assert hasattr(dac, "channels")
      dac.close()
  