def test_setting_formula_parses_formula_sets_dependencies_then_sets_python_formula(
self, mock_parser, mock_get_python_formula_from_parse_tree,
mock_get_dependencies_from_parse_tree):
call_order = []
def get_add_call(name, return_value):
def add_call(*_):
call_order.append(name)
return return_value
return add_call
mock_get_python_formula_from_parse_tree.side_effect = get_add_call(
'formula', sentinel.formula)
mock_get_dependencies_from_parse_tree.side_effect = get_add_call(
'dependencies', sentinel.dependencies)
cell = Cell()
cell.python_formula = '=something'
cell.formula = '=k'
self.assertCalledOnce(mock_parser.parse, '=k')
self.assertCalledOnce(mock_get_python_formula_from_parse_tree,
mock_parser.parse.return_value)
self.assertEquals(cell._python_formula, sentinel.formula)
self.assertCalledOnce(mock_get_dependencies_from_parse_tree,
mock_parser.parse.return_value)
self.assertEquals(cell.dependencies, sentinel.dependencies)
self.assertEquals(call_order, ['dependencies', 'formula'])
def test_setting_formula_with_syntax_error_sets_appropriate_raise_in_python_formula_and_clears_dependencies(self):
cell = Cell()
cell.dependencies = 'before'
cell.python_formula = 'before'
cell.formula = '=#NULL!'
self.assertEquals(
cell.python_formula,
'_raise(FormulaError("Error in formula at position 2: unexpected \'#NULL!\'"))'
)
self.assertEquals(cell.dependencies, [])
cell.dependencies = 'before'
cell.python_formula = 'before'
cell.formula = '=#Invalid!'
self.assertEquals(
cell.python_formula,
'_raise(FormulaError("#Invalid! cell reference in formula"))'
)
self.assertEquals(cell.dependencies, [])
cell.dependencies = 'before'
cell.python_formula = 'before'
cell.formula = '=#Deleted!'
self.assertEquals(
cell.python_formula,
'_raise(FormulaError("#Deleted! cell reference in formula"))'
)
self.assertEquals(cell.dependencies, [])
def test_setting_formula_to_constant_clears_python_formula(self):
cell = Cell()
cell.python_formula = 'something'
cell.formula = 'k'
self.assertEquals(cell.python_formula, None)
def test_recalc_cell_catches_cell_errors_and_adds_them_to_console(self):
cell = Cell()
cell.formula = "=123"
cell.python_formula = '_raise(Exception("OMGWTFBBQ"))'
cell.error = 'old error, just hanging around...'
worksheet = Worksheet()
location = (1, 11)
worksheet[location] = cell
# Mocked out to avoid explosion -- tested in another unit test.
node = Mock()
node.parents = []
graph = {location: node}
context = {'worksheet': worksheet, "_raise": _raise}
worksheet.add_console_text = Mock()
recalculate_cell(location, Mock(), graph, context)
self.assertEqual(worksheet[location].error, 'Exception: OMGWTFBBQ')
expected_error_text = "Exception: OMGWTFBBQ\n Formula '%s' in A11\n" % (
cell.formula)
self.assertCalledOnce(worksheet.add_console_text, expected_error_text)
self.assertEquals(worksheet[location].value, undefined)
def test_eq_neq(self):
cell1 = Cell()
cell1.formula = '=formula'
cell2 = Cell()
cell2.formula = '=formula'
self.assertTrue(cell1 == cell2)
self.assertFalse(cell1 != cell2)
cell1.value = 10
self.assertFalse(cell1 == cell2)
self.assertTrue(cell1 != cell2)
cell2.value = 10
self.assertTrue(cell1 == cell2)
self.assertFalse(cell1 != cell2)
cell1.formatted_value = 'formatted'
self.assertFalse(cell1 == cell2)
self.assertTrue(cell1 != cell2)
cell2.formatted_value = 'formatted'
self.assertTrue(cell1 == cell2)
self.assertFalse(cell1 != cell2)
cell1.error = 'this error'
self.assertFalse(cell1 == cell2)
self.assertTrue(cell1 != cell2)
cell2.error = 'this error'
self.assertTrue(cell1 == cell2)
self.assertFalse(cell1 != cell2)
self.assertFalse(cell1 == 'hello')
self.assertTrue(cell1 != 'hello')
def test_recalc_cell_catches_cell_errors_and_adds_them_to_console(self):
cell = Cell()
cell.formula = "=123"
cell.python_formula = '_raise(Exception("OMGWTFBBQ"))'
cell.error = 'old error, just hanging around...'
worksheet = Worksheet()
location = (1, 11)
worksheet[location] = cell
# Mocked out to avoid explosion -- tested in another unit test.
node = Mock()
node.parents = []
graph = {location: node }
context = { 'worksheet': worksheet, "_raise": _raise }
worksheet.add_console_text = Mock()
recalculate_cell(location, Mock(), graph, context)
self.assertEqual(
worksheet[location].error,
'Exception: OMGWTFBBQ'
)
expected_error_text = "Exception: OMGWTFBBQ\n Formula '%s' in A11\n" % (
cell.formula)
self.assertCalledOnce(worksheet.add_console_text, expected_error_text)
self.assertEquals(worksheet[location].value, undefined)
def test_recalc_cell_should_clear_cell_error_and_not_add_to_console_text_on_eval_succeeding(self):
cell = Cell()
cell.formula = '=123'
cell.error = 'old error, just hanging around...'
worksheet = Worksheet()
location = (1, 11)
worksheet[location] = cell
node = Mock()
node.parents = []
graph = {location: node }
context = { 'worksheet': { location: cell, } }
recalculate_cell(location, Mock(), graph, context)
self.assertEqual(
worksheet[location].error,
None
)
self.assertEqual(
worksheet[location].value,
123
)
self.assertEqual(
worksheet._console_text, ''
)
def test_setting_formula_to_constant_clears_python_formula(self):
cell = Cell()
cell.python_formula = 'something'
cell.formula = 'k'
self.assertEquals(cell.python_formula, None)
def test_setting_formatted_value_to_non_string_explodes(self):
class TestObject(object):
pass
cell = Cell()
with self.assertRaises(TypeError) as mngr:
cell.formatted_value = TestObject()
self.assertEquals(str(mngr.exception), 'cell formatted_value must be str or unicode')
def test_setting_python_formula_to_non_string_explodes(self):
cell = Cell()
with self.assertRaises(TypeError) as mngr:
cell.python_formula = type
self.assertEquals(str(mngr.exception),
'cell python_formula must be str or unicode')
def test_setting_formula_to_none_works_and_sets_python_formula_to_none(self):
cell = Cell()
cell.python_formula = 'something'
cell.formula = None
self.assertEquals(cell.formula, None)
self.assertEquals(cell.python_formula, None)
def test_setting_formula_to_none_works_and_sets_python_formula_to_none(
self):
cell = Cell()
cell.python_formula = 'something'
cell.formula = None
self.assertEquals(cell.formula, None)
self.assertEquals(cell.python_formula, None)
def test_clear_value_clears_value_but_not_formatted_value(self):
cell = Cell()
cell.value = 29
cell.formatted_value = "wibble"
cell.clear_value()
self.assertEquals(cell.value, undefined)
self.assertEquals(cell.formatted_value, "wibble")
def test_setting_python_formula_to_non_string_explodes(self):
cell = Cell()
with self.assertRaises(TypeError) as mngr:
cell.python_formula = type
self.assertEquals(
str(mngr.exception),
'cell python_formula must be str or unicode'
)
def test_setting_formatted_value_to_non_string_explodes(self):
class TestObject(object):
pass
cell = Cell()
with self.assertRaises(TypeError) as mngr:
cell.formatted_value = TestObject()
self.assertEquals(str(mngr.exception),
'cell formatted_value must be str or unicode')
def test_load_constants_should_clear_errors_for_constants(self):
cell = Cell()
cell.formula = "a constant"
cell.error = 'Ohno!'
worksheet = Worksheet()
worksheet.A1 = cell
load_constants(worksheet)
self.assertIsNone(cell.error)
def test_load_constants_should_clear_errors_for_constants(self):
cell = Cell()
cell.formula = "a constant"
cell.error = 'Ohno!'
worksheet = Worksheet()
worksheet.A1 = cell
load_constants(worksheet)
self.assertIsNone(cell.error)
def test_should_not_reprocess_locations_already_in_visited_even_if_it_is_in_worksheet(
self, mock_add_location_dependencies):
cell = Cell()
cell.formula = 'constant'
worksheet = Worksheet()
worksheet[1, 2] = cell
_generate_cell_subgraph(worksheet, sentinel.graph, (1, 2),
set([(1, 2)]), [])
self.assertFalse(mock_add_location_dependencies.called)
def test_should_not_reprocess_locations_already_in_visited_even_if_it_is_in_worksheet(
self, mock_add_location_dependencies
):
cell = Cell()
cell.formula = 'constant'
worksheet = Worksheet()
worksheet[1, 2] = cell
_generate_cell_subgraph(worksheet, sentinel.graph, (1, 2), set([(1, 2)]), [])
self.assertFalse(mock_add_location_dependencies.called)
def test_recalculate_cell_should_perform_true_division(self):
location = (1, 2)
cell = Cell()
cell.python_formula = '1/4'
context = { "worksheet": { location: cell } }
# Mocked out to avoid explosion -- tested in another unit test.
node = Mock()
node.parents = []
recalculate_cell(location, None, { location: node }, context)
self.assertEquals(cell.value, 0.25)
def test_recalculate_cell_should_perform_true_division(self):
location = (1, 2)
cell = Cell()
cell.python_formula = '1/4'
context = {"worksheet": {location: cell}}
# Mocked out to avoid explosion -- tested in another unit test.
node = Mock()
node.parents = []
recalculate_cell(location, None, {location: node}, context)
self.assertEquals(cell.value, 0.25)
def test_recalculate_cell_evals_python_formula_in_context_and_puts_results_in_worksheet(self):
location = (1, 2)
cell = Cell()
cell.python_formula = '100 + fred'
context = { 'fred': 23, "worksheet": { location: cell } }
# Mocked out to avoid explosion -- tested in another unit test.
node = Mock()
node.parents = []
recalculate_cell(location, None, { location: node }, context)
self.assertEquals(cell.value, 123)
def test_run_worksheet_with_overrides(self, mock_urllib2):
self.maxDiff = None
cellA2 = Cell()
cellA2.formula = '1'
cellA2.value = 1
cellC3 = Cell()
cellC3.formula = '5'
cellC3.value = 5
cellE4 = Cell()
cellE4.formula = '=A2 + C3'
cellE4.value = 6
overrides = {
(1, 2): '11',
(3, 3): 55,
(4, 1): '="abc"',
'dirigible_l337_private_key': sentinel.private_key
}
result_of_calculation_json = '''{
"name": "Untitled",
"1": {
"2": 11
},
"3": {
"3": 55
},
"4": {
"1": "abc"
},
"5": {
"4": 66
}
}'''
mock_opener = mock_urllib2.build_opener.return_value
mock_urlopen_file = mock_opener.open.return_value
mock_urlopen_file.read.return_value = result_of_calculation_json
worksheet_url = 'ws_url/'
result = run_worksheet(worksheet_url, overrides, sentinel.private_key)
target_url = '%sv%s/json/' % (worksheet_url, CURRENT_API_VERSION)
self.assertCalledOnce(mock_opener.open, target_url, data=urlencode(overrides))
self.assertEquals(type(result), Worksheet)
expected_sheet = Worksheet()
expected_sheet.name = 'Untitled'
expected_sheet[1, 2].value = 11
expected_sheet[3, 3].value = 55
expected_sheet[4, 1].value = 'abc'
expected_sheet[5, 4].value = 66
self.assertEquals(result, expected_sheet)
def test_recalculate_cell_evals_python_formula_in_context_and_puts_results_in_worksheet(
self):
location = (1, 2)
cell = Cell()
cell.python_formula = '100 + fred'
context = {'fred': 23, "worksheet": {location: cell}}
# Mocked out to avoid explosion -- tested in another unit test.
node = Mock()
node.parents = []
recalculate_cell(location, None, {location: node}, context)
self.assertEquals(cell.value, 123)
def test_recalculate_cell_should_remove_nodes_from_dependency_graph(self):
location = (1, 2)
cell = Cell()
cell.formula = '=123'
leaf_queue = Queue()
parent = Mock()
parent_loc = (2, 3)
node = Mock()
node.parents = set([(parent_loc)])
graph = { location: node, parent_loc: parent }
context = { 'worksheet': { location: cell, } }
recalculate_cell(location, leaf_queue, graph, context)
self.assertEquals( node.remove_from_parents.call_args, (([parent], leaf_queue,), {}) )
def test_setitem_on_nonexistent_cell(self):
cell_range = CellRange(self.ws, (2, 2), (10, 9))
cell_range[2, 2].value = 'new val'
self.assertEquals(self.ws[3, 3].value, 'new val')
new_cell = Cell()
cell_range[2, 3] = new_cell
self.assertEquals(self.ws[3, 4], new_cell)
def test_setitem_on_locations_should_accept_cell_instances(self):
ws = Worksheet()
ws.to_location = Mock(return_value=(1, 2))
cell = Cell()
ws[3, 4] = cell
self.assertEquals(ws.to_location.call_args_list, [(((3, 4),), {})])
self.assertEquals(ws.keys(), [(1, 2)])
def test_initialisation(self):
self.assertEquals(Cell().formula, None)
self.assertEquals(Cell().python_formula, None)
self.assertEquals(Cell().dependencies, [])
self.assertEquals(Cell().value, undefined)
self.assertEquals(Cell().formatted_value, u'')
self.assertEquals(Cell().error, None)
def test_clear_clears_stuff(self):
cell = Cell()
cell.value = 29
cell.formula = 'e equals emcee squared'
cell.python_formula = 'e equals emcee squared'
cell.dependencies = [(1, 1), (2, 2)]
cell.formatted_value = "wibble"
cell.error = 'a spear'
cell.clear()
self.assertEquals(cell.value, undefined)
self.assertEquals(cell.formula, None)
self.assertEquals(cell.python_formula, None)
self.assertEquals(Cell().dependencies, [])
self.assertEquals(cell.formatted_value, u"")
self.assertEquals(cell.error, None)
def test_recalculate_cell_should_remove_nodes_from_dependency_graph(self):
location = (1, 2)
cell = Cell()
cell.formula = '=123'
leaf_queue = Queue()
parent = Mock()
parent_loc = (2, 3)
node = Mock()
node.parents = set([(parent_loc)])
graph = {location: node, parent_loc: parent}
context = {
'worksheet': {
location: cell,
}
}
recalculate_cell(location, leaf_queue, graph, context)
self.assertEquals(node.remove_from_parents.call_args, ((
[parent],
leaf_queue,
), {}))
def test_sheet_to_ui_json_grid_data_should_not_include_totally_empty_cells(
self):
worksheet = Worksheet()
worksheet.A1 = Cell()
expected_json_contents = {
'bottom': 10,
'left': 0,
'right': 10,
'topmost': 0
}
self.assertEquals(
json.loads(sheet_to_ui_json_grid_data(worksheet, (0, 0, 10, 10))),
expected_json_contents)
def test_recalc_cell_should_clear_cell_error_and_not_add_to_console_text_on_eval_succeeding(
self):
cell = Cell()
cell.formula = '=123'
cell.error = 'old error, just hanging around...'
worksheet = Worksheet()
location = (1, 11)
worksheet[location] = cell
node = Mock()
node.parents = []
graph = {location: node}
context = {
'worksheet': {
location: cell,
}
}
recalculate_cell(location, Mock(), graph, context)
self.assertEqual(worksheet[location].error, None)
self.assertEqual(worksheet[location].value, 123)
self.assertEqual(worksheet._console_text, '')
def test_setting_formula_parses_formula_sets_dependencies_then_sets_python_formula(
self, mock_parser, mock_get_python_formula_from_parse_tree, mock_get_dependencies_from_parse_tree
):
call_order = []
def get_add_call(name, return_value):
def add_call(*_):
call_order.append(name)
return return_value
return add_call
mock_get_python_formula_from_parse_tree.side_effect = get_add_call('formula', sentinel.formula)
mock_get_dependencies_from_parse_tree.side_effect = get_add_call('dependencies', sentinel.dependencies)
cell = Cell()
cell.python_formula = '=something'
cell.formula = '=k'
self.assertCalledOnce(mock_parser.parse, '=k')
self.assertCalledOnce(mock_get_python_formula_from_parse_tree,
mock_parser.parse.return_value
)
self.assertEquals(
cell._python_formula,
sentinel.formula
)
self.assertCalledOnce(mock_get_dependencies_from_parse_tree,
mock_parser.parse.return_value
)
self.assertEquals(
cell.dependencies,
sentinel.dependencies
)
self.assertEquals(call_order, ['dependencies', 'formula'])
def test_clear_value_clears_value_but_not_formatted_value(self):
cell = Cell()
cell.value = 29
cell.formatted_value = "wibble"
cell.clear_value()
self.assertEquals(cell.value, undefined)
self.assertEquals(cell.formatted_value, "wibble")
def test_setting_value_to_undefined_sets_formatted_value_to_empty_string(self):
cell = Cell()
cell._set_formatted_value = Mock()
cell.value = undefined
self.assertCalledOnce(cell._set_formatted_value, u'')
def test_setting_value_sets_formatted_value_to_unicode_version(self):
cell = Cell()
cell._set_formatted_value = Mock()
cell.value = sentinel.value
self.assertCalledOnce(cell._set_formatted_value, unicode(sentinel.value))
def test_setting_formatted_value_to_none(self):
cell = Cell()
cell.formatted_value = None
self.assertEquals(cell.formatted_value, '')
def test_getitem_creates_cells(self):
ws = Worksheet()
try:
ws[1, 2].value = Cell()
except KeyError:
self.fail('Did not create cell on request')
def test_setting_formatted_value_to_string_passes_through(self):
cell = Cell()
cell.formatted_value = 'this > string'
self.assertEquals(cell.formatted_value, 'this > string')
def test_setting_formula_to_string_passes_through(self):
cell = Cell()
cell.formula = 'this < string'
self.assertEquals(cell.formula, 'this < string')
def test_setting_formatted_value_to_none(self):
cell = Cell()
cell.formatted_value = None
self.assertEquals(cell.formatted_value, '')
def test_setting_value_to_ws_doesnt_die(self):
# This is actually mostly testing that it doesn't explode
cell = Cell()
ws = Worksheet()
cell.value = ws
self.assertEquals(cell.formatted_value, unicode(ws))
def test_can_use_unicode_in_formula(self):
cell = Cell()
cell.formula = u'Sacr\xe9 bleu!'
self.assertEquals(cell.formula, u'Sacr\xe9 bleu!')
def test_eq_neq(self):
cell1 = Cell()
cell1.formula = '=formula'
cell2 = Cell()
cell2.formula = '=formula'
self.assertTrue(cell1 == cell2)
self.assertFalse(cell1 != cell2)
cell1.value = 10
self.assertFalse(cell1 == cell2)
self.assertTrue(cell1 != cell2)
cell2.value = 10
self.assertTrue(cell1 == cell2)
self.assertFalse(cell1 != cell2)
cell1.formatted_value = 'formatted'
self.assertFalse(cell1 == cell2)
self.assertTrue(cell1 != cell2)
cell2.formatted_value = 'formatted'
self.assertTrue(cell1 == cell2)
self.assertFalse(cell1 != cell2)
cell1.error = 'this error'
self.assertFalse(cell1 == cell2)
self.assertTrue(cell1 != cell2)
cell2.error = 'this error'
self.assertTrue(cell1 == cell2)
self.assertFalse(cell1 != cell2)
self.assertFalse(cell1 == 'hello')
self.assertTrue(cell1 != 'hello')
def test_setting_formatted_value_to_string_passes_through(self):
cell = Cell()
cell.formatted_value = 'this > string'
self.assertEquals(cell.formatted_value, 'this > string')
def test_repr(self):
cell = Cell()
cell.formula = 'f'
self.assertEquals(
repr(cell),
"<Cell formula=f value=<undefined> formatted_value=u''>")
cell = Cell()
cell.value = 'v'
self.assertEquals(
repr(cell), "<Cell formula=None value='v' formatted_value=u'v'>")
cell = Cell()
cell.value = 23
self.assertEquals(
repr(cell), "<Cell formula=None value=23 formatted_value=u'23'>")
cell = Cell()
cell.formula = 'f'
cell.value = 'v'
self.assertEquals(repr(cell),
"<Cell formula=f value='v' formatted_value=u'v'>")
cell = Cell()
cell.formula = 'f'
cell.value = 'v'
cell.formatted_value = u'fv'
self.assertEquals(repr(cell),
"<Cell formula=f value='v' formatted_value=u'fv'>")
cell = Cell()
cell.formula = 'f'
cell.value = 'v'
cell.formatted_value = u'fv'
cell.error = 'e'
self.assertEquals(
repr(cell),
"<Cell formula=f value='v' formatted_value=u'fv' error='e'>")
def test_can_use_unicode_in_formula(self):
cell = Cell()
cell.formula = u'Sacr\xe9 bleu!'
self.assertEquals(cell.formula, u'Sacr\xe9 bleu!')
def test_setting_formula_with_syntax_error_sets_appropriate_raise_in_python_formula_and_clears_dependencies(
self):
cell = Cell()
cell.dependencies = 'before'
cell.python_formula = 'before'
cell.formula = '=#NULL!'
self.assertEquals(
cell.python_formula,
'_raise(FormulaError("Error in formula at position 2: unexpected \'#NULL!\'"))'
)
self.assertEquals(cell.dependencies, [])
cell.dependencies = 'before'
cell.python_formula = 'before'
cell.formula = '=#Invalid!'
self.assertEquals(
cell.python_formula,
'_raise(FormulaError("#Invalid! cell reference in formula"))')
self.assertEquals(cell.dependencies, [])
cell.dependencies = 'before'
cell.python_formula = 'before'
cell.formula = '=#Deleted!'
self.assertEquals(
cell.python_formula,
'_raise(FormulaError("#Deleted! cell reference in formula"))')
self.assertEquals(cell.dependencies, [])
def test_repr(self):
cell = Cell()
cell.formula = 'f'
self.assertEquals(repr(cell), "<Cell formula=f value=<undefined> formatted_value=u''>")
cell = Cell()
cell.value = 'v'
self.assertEquals(repr(cell), "<Cell formula=None value='v' formatted_value=u'v'>")
cell = Cell()
cell.value = 23
self.assertEquals(repr(cell), "<Cell formula=None value=23 formatted_value=u'23'>")
cell = Cell()
cell.formula = 'f'
cell.value = 'v'
self.assertEquals(repr(cell), "<Cell formula=f value='v' formatted_value=u'v'>")
cell = Cell()
cell.formula = 'f'
cell.value = 'v'
cell.formatted_value = u'fv'
self.assertEquals(repr(cell), "<Cell formula=f value='v' formatted_value=u'fv'>")
cell = Cell()
cell.formula = 'f'
cell.value = 'v'
cell.formatted_value = u'fv'
cell.error = 'e'
self.assertEquals(repr(cell), "<Cell formula=f value='v' formatted_value=u'fv' error='e'>")
def test_clear_clears_stuff(self):
cell = Cell()
cell.value = 29
cell.formula = 'e equals emcee squared'
cell.python_formula = 'e equals emcee squared'
cell.dependencies = [(1, 1), (2, 2)]
cell.formatted_value = "wibble"
cell.error = 'a spear'
cell.clear()
self.assertEquals(cell.value, undefined)
self.assertEquals(cell.formula, None)
self.assertEquals(cell.python_formula, None)
self.assertEquals(Cell().dependencies, [])
self.assertEquals(cell.formatted_value, u"")
self.assertEquals(cell.error, None)
def test_setting_value_to_ws_doesnt_die(self):
# This is actually mostly testing that it doesn't explode
cell = Cell()
ws = Worksheet()
cell.value = ws
self.assertEquals(cell.formatted_value, unicode(ws))
def test_setting_value_to_undefined_sets_formatted_value_to_empty_string(
self):
cell = Cell()
cell._set_formatted_value = Mock()
cell.value = undefined
self.assertCalledOnce(cell._set_formatted_value, u'')
def test_setting_formatted_value_to_unicode(self):
cell = Cell()
cell.formatted_value = u'Sacr\xe9 bleu!'
self.assertEquals(cell.formatted_value, u'Sacr\xe9 bleu!')
def test_setting_value_sets_formatted_value_to_unicode_version(self):
cell = Cell()
cell._set_formatted_value = Mock()
cell.value = sentinel.value
self.assertCalledOnce(cell._set_formatted_value,
unicode(sentinel.value))
def test_setting_formatted_value_to_unicode(self):
cell = Cell()
cell.formatted_value = u'Sacr\xe9 bleu!'
self.assertEquals(cell.formatted_value, u'Sacr\xe9 bleu!')
def test_setting_formula_to_string_passes_through(self):
cell = Cell()
cell.formula = 'this < string'
self.assertEquals(cell.formula, 'this < string')