def test_attributes(self, expression):
expr = te.Expression(expression, varnames='beta a')
assert isinstance(expr, te.Expression)
assert expr.varnames == ('beta', 'a')
assert expr.body == expression
assert str(expr) == expression
assert repr(expr) == '<Expression: {}>'.format(expr)
with pytest.raises(AttributeError, match='writable'):
expr.varnames = ('a', 'b')
with pytest.raises(AttributeError, match='writable'):
expr.body = 'x + y'
def test_null_byte_in_varname(self):
with pytest.raises(ValueError, match='null byte'):
te.Expression('1+alpha * b', 'a\x00lpha b')
def test_null_byte_in_body(self):
with pytest.raises(ValueError, match='null byte'):
te.Expression('1\x00+1')
def test_empty_body(self):
with pytest.raises(ValueError, match='position 1'):
te.Expression('')
def test_parse_error(self):
with pytest.raises(ValueError, match='position 4'):
te.Expression('(5+5')
def test_input_types(self):
assert te.eval(u'1+1') == 2
assert te.eval('1+1') == 2
assert te.eval(te.Expression('3+6')) == 9
def test_eval_missing_var(self, expression):
expr = te.Expression(expression, varnames='beta a')
with pytest.raises(TypeError, match='"beta"'):
te.eval(expr, a=4)
def test_eval_with_kwargs(self, expression):
expr = te.Expression(expression, varnames='beta a')
assert te.eval(expr, a=4, beta=9) == approx(.8888888)
assert te.eval(expr, a=9, beta=-1) == approx(-13.92839)