How to use the cantools._main function in cantools

IO_DEBUG(
    IO_DEBUG_test_unsigned: 1,
    IO_DEBUG_test_enum: 'IO_DEBUG_test2_enum_two',
    IO_DEBUG_test_signed: 3,
    IO_DEBUG_test_float: 2.0
)
  vcan0  1F4   [3]  01 02 03 :: unpack requires at least 32 bits to unpack (got 24)
  vcan0  1F3   [3]  01 02 03 :: Unknown frame id 499 (0x1f3)
"""

        stdout = StringIO()

        with patch('sys.stdin', StringIO(input_data)):
            with patch('sys.stdout', stdout):
                with patch('sys.argv', argv):
                    cantools._main()
                    actual_output = stdout.getvalue()
                    self.assertEqual(actual_output, expected_output)

fuzzer_mk = basename + '_fuzzer.mk'

            if os.path.exists(database_h):
                os.remove(database_h)

            if os.path.exists(database_c):
                os.remove(database_c)

            if os.path.exists(fuzzer_c):
                os.remove(fuzzer_c)

            if os.path.exists(fuzzer_mk):
                os.remove(fuzzer_mk)

            with patch('sys.argv', argv):
                cantools._main()

            if sys.version_info[0] > 2:
                self.assert_files_equal(database_h,
                                        'tests/files/c_source/' + database_h)
                self.assert_files_equal(database_c,
                                        'tests/files/c_source/' + database_c)

            self.assertFalse(os.path.exists(fuzzer_c))
            self.assertFalse(os.path.exists(fuzzer_mk))

MODULE_TEMP_34: 23066
)
  vcan0  401   [6]  23 00 59 99 5C 5A ::
BATTERY_VT(
    BATTERY_VT_INDEX: 35,
    MODULE_VOLTAGE_35: 39257,
    MODULE_TEMP_35: 23132
)
"""

        stdout = StringIO()

        with patch('sys.stdin', StringIO(input_data)):
            with patch('sys.stdout', stdout):
                with patch('sys.argv', argv):
                    cantools._main()
                    actual_output = stdout.getvalue()
                    self.assertEqual(actual_output, expected_output)

t       +-- signal_without_sender
     e

  Signal tree:

    -- {root}
       +-- signal_without_sender

  ------------------------------------------------------------------------
"""

        stdout = StringIO()

        with patch('sys.stdout', stdout):
            with patch('sys.argv', argv):
                cantools._main()
                actual_output = stdout.getvalue()
                self.assertEqual(actual_output, expected_output)

expected_output = """\
  vcan0  0C8   [8]  F0 00 00 00 00 00 00 00 :: SENSOR_SONARS(SENSOR_SONARS_mux: 0, SENSOR_SONARS_err_count: 15, SENSOR_SONARS_left: 0.0, SENSOR_SONARS_middle: 0.0, SENSOR_SONARS_right: 0.0, SENSOR_SONARS_rear: 0.0)
  vcan0  064   [10]  F0 01 FF FF FF FF FF FF FF FF :: DRIVER_HEARTBEAT(DRIVER_HEARTBEAT_cmd: 240)
  vcan0  ERROR

  vcan0  1F4   [4]  01 02 03 04 :: IO_DEBUG(IO_DEBUG_test_unsigned: 1, IO_DEBUG_test_enum: 'IO_DEBUG_test2_enum_two', IO_DEBUG_test_signed: 3, IO_DEBUG_test_float: 2.0)
  vcan0  1F4   [3]  01 02 03 :: unpack requires at least 32 bits to unpack (got 24)
  vcan0  1F3   [3]  01 02 03 :: Unknown frame id 499 (0x1f3)
"""

        stdout = StringIO()

        with patch('sys.stdin', StringIO(input_data)):
            with patch('sys.stdout', stdout):
                with patch('sys.argv', argv):
                    cantools._main()
                    actual_output = stdout.getvalue()
                    self.assertEqual(actual_output, expected_output)

'--bit-fields',
                '--database-name', '{}_bit_fields'.format(database),
                'tests/files/dbc/{}.dbc'.format(database)
            ]

            database_h = database + '_bit_fields.h'
            database_c = database + '_bit_fields.c'

            if os.path.exists(database_h):
                os.remove(database_h)

            if os.path.exists(database_c):
                os.remove(database_c)

            with patch('sys.argv', argv):
                cantools._main()

            if sys.version_info[0] > 2:
                self.assert_files_equal(database_h,
                                        'tests/files/c_source/' + database_h)
                self.assert_files_equal(database_c,
                                        'tests/files/c_source/' + database_c)

fuzzer_mk = basename + '_fuzzer.mk'

            if os.path.exists(database_h):
                os.remove(database_h)

            if os.path.exists(database_c):
                os.remove(database_c)

            if os.path.exists(fuzzer_c):
                os.remove(fuzzer_c)

            if os.path.exists(fuzzer_mk):
                os.remove(fuzzer_mk)

            with patch('sys.argv', argv):
                cantools._main()

            if sys.version_info[0] > 2:
                self.assert_files_equal(database_h,
                                        'tests/files/c_source/' + database_h)
                self.assert_files_equal(database_c,
                                        'tests/files/c_source/' + database_c)

            self.assertFalse(os.path.exists(fuzzer_c))
            self.assertFalse(os.path.exists(fuzzer_mk))

t       +-- signal_without_sender
     e

  Signal tree:

    -- {root}
       +-- signal_without_sender

  ------------------------------------------------------------------------
"""

        stdout = StringIO()

        with patch('sys.stdout', stdout):
            with patch('sys.argv', argv):
                cantools._main()
                actual_output = stdout.getvalue()
                self.assertEqual(actual_output, expected_output)

vcan0  401   [6]  1C 00 7E 99 50 5A :: BATTERY_VT(BATTERY_VT_INDEX: 28, MODULE_VOLTAGE_28: 39294, MODULE_TEMP_28: 23120)
  vcan0  401   [6]  1D 00 39 9A 21 5A :: BATTERY_VT(BATTERY_VT_INDEX: 29, MODULE_VOLTAGE_29: 39481, MODULE_TEMP_29: 23073)
  vcan0  401   [6]  1E 00 44 99 F9 59 :: BATTERY_VT(BATTERY_VT_INDEX: 30, MODULE_VOLTAGE_30: 39236, MODULE_TEMP_30: 23033)
  vcan0  401   [6]  1F 00 60 99 1B 5A :: BATTERY_VT(BATTERY_VT_INDEX: 31, MODULE_VOLTAGE_31: 39264, MODULE_TEMP_31: 23067)
  vcan0  401   [6]  20 00 42 99 0A 5A :: BATTERY_VT(BATTERY_VT_INDEX: 32, MODULE_VOLTAGE_32: 39234, MODULE_TEMP_32: 23050)
  vcan0  401   [6]  21 00 C3 9A 33 5A :: BATTERY_VT(BATTERY_VT_INDEX: 33, MODULE_VOLTAGE_33: 39619, MODULE_TEMP_33: 23091)
  vcan0  401   [6]  22 00 3D 99 1A 5A :: BATTERY_VT(BATTERY_VT_INDEX: 34, MODULE_VOLTAGE_34: 39229, MODULE_TEMP_34: 23066)
  vcan0  401   [6]  23 00 59 99 5C 5A :: BATTERY_VT(BATTERY_VT_INDEX: 35, MODULE_VOLTAGE_35: 39257, MODULE_TEMP_35: 23132)
"""

        stdout = StringIO()

        with patch('sys.stdin', StringIO(input_data)):
            with patch('sys.stdout', stdout):
                with patch('sys.argv', argv):
                    cantools._main()
                    actual_output = stdout.getvalue()
                    self.assertEqual(actual_output, expected_output)

'tests/files/dbc/{}.dbc'.format(database)
            ]

            database_h = database + '.h'
            database_c = database + '.c'
            expected_database_h = database + '_no_floating_point_numbers.h'
            expected_database_c = database + '_no_floating_point_numbers.c'

            if os.path.exists(database_h):
                os.remove(database_h)

            if os.path.exists(database_c):
                os.remove(database_c)

            with patch('sys.argv', argv):
                cantools._main()

            if sys.version_info[0] > 2:
                self.assert_files_equal(
                    database_h,
                    'tests/files/c_source/' + expected_database_h)
                self.assert_files_equal(
                    database_c,
                    'tests/files/c_source/' + expected_database_c)