How to use the goodtables.cells function in goodtables

def test_check_non_matching_header_order_fields_problem(log):
    cells = [
        goodtables.cells.create_cell('name1', field=Field({'name': 'name4'}), column_number=1),
        goodtables.cells.create_cell('name2', field=Field({'name': 'name1'}), column_number=2),
        goodtables.cells.create_cell('name3', column_number=3),
    ]
    non_matching_header = NonMatchingHeader(order_fields=True)
    errors = non_matching_header.check_headers(cells)
    assert log(errors) == [
        (None, 2, 'non-matching-header'),
    ]
    # New header cells will be added by the non-matching-header check because
    # there are no fields for the "name2" and "name3" headers
    assert len(cells) == 4

def test_truncated_values(value):
    cell = goodtables.cells.create_cell('value', value)
    errors = TruncatedValue().check_row([cell])
    assert len(errors) == 1
    assert errors[0].code == 'truncated-value'

def test_check_blank_header_problem(log):
    errors = []
    cells = [
        goodtables.cells.create_cell('', column_number=1),
    ]
    errors = blank_header(cells)
    assert log(errors) == [
        (None, 1, 'blank-header'),
    ]
    assert len(cells) == 1

def test_check_blank_row_problem(log):
    cells = [
        goodtables.cells.create_cell('name1', '', row_number=1),
    ]
    errors = blank_row(cells)
    assert log(errors) == [
        (1, None, 'blank-row'),
    ]
    assert len(cells) == 0

def test_check_missing_header_problem(log):
    cells = [
        goodtables.cells.create_cell('name1', field=Field({'name': 'name1'}), column_number=1),
        goodtables.cells.create_cell(None, field=Field({'name': 'name2'}), column_number=2),
    ]
    errors = missing_header(cells, None)
    assert log(errors) == [
        (None, 2, 'missing-header'),
    ]
    assert len(cells) == 1

def test_check_extra_value(log):
    cells = [
        goodtables.cells.create_cell('name1', 'value'),
        goodtables.cells.create_cell('name2', 'value'),
    ]
    extra_value = ExtraValue()
    errors = extra_value.check_row(cells)
    assert log(errors) == []
    assert len(cells) == 2

def test_check_non_matching_header(log):
    cells = [
        goodtables.cells.create_cell('name1', field=Field({'name': 'name1'}), column_number=1),
        goodtables.cells.create_cell('name2', field=Field({'name': 'name2'}), column_number=2),
        goodtables.cells.create_cell('name3', column_number=3),
    ]
    non_matching_header = NonMatchingHeader()
    errors = non_matching_header.check_headers(cells)
    assert log(errors) == []
    assert len(cells) == 3

def test_check_truncated_value_with_dates():
    # There was a bug where we didn't catch the correct exception when calling
    # int(date)
    cell = goodtables.cells.create_cell(
        'date',
        datetime.datetime.now()
    )
    errors = TruncatedValue().check_row([cell])

    assert not errors

def test_check_duplicate_header(log):
    cells = [
        goodtables.cells.create_cell('name1', column_number=1),
        goodtables.cells.create_cell('name2', column_number=2),
    ]
    errors = duplicate_header(cells)
    assert log(errors) == []
    assert len(cells) == 2