def test_ast_expression_getslice_error(self):
with self.assertRaises(errors.EvaluationError):
ast.GetSliceExpression(
context, ast.LiteralExpressionBase.from_value(context, 1.0))
with self.assertRaises(errors.EvaluationError):
ast.GetSliceExpression(
context, ast.LiteralExpressionBase.from_value(context, None))
with self.assertRaises(errors.EvaluationError):
ast.GetSliceExpression(
context, ast.LiteralExpressionBase.from_value(context, True))
def test_ast_expression_getslice_safe(self):
sym_name = ''.join(
random.choice(string.ascii_letters) for _ in range(10))
container = ast.SymbolExpression(context, sym_name)
start = ast.FloatExpression(context, 0)
stop = ast.FloatExpression(context, -1)
get_slice = ast.GetSliceExpression(context, container, start, stop)
with self.assertRaises(errors.EvaluationError):
get_slice.evaluate({sym_name: None})
get_slice = ast.GetSliceExpression(context,
container,
start,
stop,
safe=True)
self.assertIsNone(get_slice.evaluate({sym_name: None}))
def test_ast_expression_getslice(self):
ary_value = tuple(
random.choice(string.ascii_letters) for _ in range(12))
str_value = ''.join(ary_value)
cases = (
(ary_value, str_value),
(None, 0, 2),
(None, -1, -3),
)
for container, start, end in itertools.product(*cases):
get_slice = ast.GetSliceExpression(
context,
ast.LiteralExpressionBase.from_value(context, container),
start=(None if start is None else
ast.LiteralExpressionBase.from_value(context, start)),
stop=(None if end is None else
ast.LiteralExpressionBase.from_value(context, end)))
self.assertEqual(get_slice.evaluate({}), container[start:end])